FSC100 Exam Review PDF

**Week 7-7a: Types of Evidence:** Slide 1: Defining Evidence: - '*Evidentia'*: to be visible - '*Videre"*: to see - Anything can be evidence, can be "invisible" too (think of fingerprints) - Evidence: "Any information or material relied on in legal proceedings to prove or dispro...

**Week 7-7a: Types of Evidence:** Slide 1: Defining Evidence: - '*Evidentia'*: to be visible - '*Videre"*: to see - Anything can be evidence, can be "invisible" too (think of fingerprints) - Evidence: "Any information or material relied on in legal proceedings to prove or disprove a fact or legal argument" Slide 2: Types of Evidence - \(1) Testimonial evidence - 'Oral evidence' or 'viva voce evidence' - Evidence given verbally by a witness during testimony - \(2) Documentary evidence - Consist of documents of any kind -Handwritten or mechanically produced (text messages, something photocopied, laptop, typewriter) -Example: medical records, affidavit - \(3) Real evidence - Physical evidence (generally covering items of non-living origin) - Biological evidence (any evidence that originates from a living source) Slide 3: Real Evidence - Some texts call this 'physical evidence' without further categorization - Evidence that crime scene investigators most concerned with - Collection and preservation at the crime scene - Analysis in the lab - Real evidence may be: - Physical - Biological Slide 4: Physical evidence (non-living origin) - Real evidence that is non-living in origin - For example: - Fingerprint originates from sweat, biological, DNA can be gathered - Glasses are non-living, - Fingerprints - Footprints - Fibers - Paint - Tire impressions - Firearms - Toolmarks - Glass Slide 5: Biological Evidence - Real evidence that originates from a living source - For example: - DNA and body fluids - Hair, skin, bone - Flora (ex. pollen) - Fauna (ex. insect larvae, maggots) - Plants - Animals - Examination and analysis may identify the living organism that deposited it - Important that crime scene investigators be aware of proper preservation and collection protocol Slide 6: Class Characteristics and Individual Characteristics - Biological evidence may be traced back to single source/common origin (DNA can be sourced back to one person) - Most often, physical evidence can only be associated with a group - Placed into a class -'Class characteristics' (ex. of class= looking for fiber, cannot link to the source, but could put it into the class of polyester material) - Individual characteristics: - Distinct differences that allow association with a single source -To high degree of certainty Slide 7: - Biological evidence as individualizing - For example: DNA analysis - Some physical evidence may be individualized: - For example: -Toolmark analysis -Bullet and casing comparisons -Tire impressions -Fingerprint analysis -Handwriting Slide 8: Other Classifications of Evidence - Three main types of evidence explored today: testimonial, documentary, and real evidence - Real evidence as physical or biological - Other terms to be familiar with: - Direct versus indirect (circumstantial) - Other classifications of real evidence -Associative -Indicative -Class, latent, and trace evidence Slide 9: Direct Versus Circumstantial - Direct evidence - Proves or disproves an important fact beyond speculation - Based on personal knowledge or observation - Refers primarily to testimonial evidence - Indirect or 'circumstantial' evidence - "Direct proof of a secondary fact which, by logical inference, demonstrates the ultimate fact is to be proven" - Relies at least partially on speculation but logically supports a fact - Refers to testimonial evidence and/or physical evidence -Ex. seeing people come into class with umbrellas, raining jackets-assumed it was raining, inferring the rain) - Most evidence examined in the crime lab is circumstantial Slide 10: Associative Evidence - Any real evidence that places an individual directly at the crime scene or as having had direct contact with the victim - Provides linkages between: -Suspect and victim -Suspect and crime scene -Victim and crime scene - For example: - Fingerprints at a crime scene - Strand of suspects hair on body of deceased Slide 11: Indicative Evidence: - Indicative evidence - Any real evidence which substantiates or proves that a certain amount of time has elapsed - Generally, no; for documentation - For example: State of decomposition, Weight loss of child during an abuse case - May be exceptions -For examples: entomology (indicative biological evidence) Slide 12: Class, Latent, and Trace evidence - Class evidence: real evidence that requires precise classification for use in Court - Requires classification into a more narrow range - Collective in nature -E.g. blood (can be furthered into blood group), semen, or hair (furthered into pubic hair, scalp hair) - Latent evidence: real evidence that is often not visible without chemical, photographic, or electronic development or enhancement (biological or physical that we can't see) - For example: Fingerprints - (Ex. hotel room and using blue lights) - Trace evidence: real evidence that must be extracted from another substance or item - Very small amounts - May be naked to the human eye - Ex. sperm extract seminal fluid and look under microscope Slide 13: - Class, latent, and trace all may describe physical or biological evidence - May be characterized in multiple ways - For example: -Evidence may be biological, associative, and trace -Evidence may be physical, trace, class, and associative - So how do we know what to call it? - Step 1: Establish evidence type -Crime scene investigators concerned with real evidence - Step 2: Physical or biological? - Step 3: What other classifications may apply? Slide 14: Importance of Real Evidence in Criminal Investigations - Real evidence is important for a number of reasons: - \(i) Linkage of persons, crime scenes, and/or objects -Locard's Exchange Principle (every contact leaves a trace) - \(ii) Providing essential information on facts of the case -*Corpus delicti* -"Body of the crime" or "element of the crime" -Establishment of proof through evidence that a crime has been committed -Must be proved by prosecutor -E.g. arson charge; corpus delicti includes evidence of fire and damage - \(iii) Revealing *modus operandi* -Preferred method of operation Slide 15: - Real evidence is important for number of reasons; - \(iv) Provide investigative leads - \(v) Prove or disprove witness statements (DV case, and arson, one individual says wife threw kerosene lamp at me and overnight there was a fire-forensic chemist could analyse if the substance kerosene or gasoline) - \(vi) Identify -Suspects (unknown or known) -Victims -Other crime scene locations - \(vii) Assist in reconstruction of the crime scene -Crime scene investigator usually more interested in "how" a crime occurred (think about blood splatter, dexter) Slide 16: Legal Issues and Evidence - Crime scene investigators must be familiar with the law and rules of evidence - What will or will not be acceptable - Burden of proving guilt on prosecutor - Crime scene investigator collects evidence - Overarching rule of Evidence Law: - Any relevant evidence should be admitted unless there is a rule of law or policy that requires exclusion Slide 17: Admissibility of Evidence - Reasons that a trial judge may deem something inadmissible: - Irrelevance -Evidence is irrelevant or immaterial to the issue before the Court - Unreliability -By its nature, evidence may be unreliable (i.e. hearsay) - Prejudice -Prejudicial quality of evidence: tendency to influence one in way that is unfair -Prejudice occurs when prejudicial quality of evidence outweighs probative value - Unfairness -Evidence must be obtained in a way that is fair (review: Search and Seizure in Canada) - Procedural unfairness -Procedural rules or other reasons that would be unfair to defense or confuse the issues **Week 7-7B: DNA and Body Fluid Evidence** Slide 1: Introduction to Forensic Biology - Serology: - The analysis of the properties and effects -Liquid state or dry state -Stain form (perhaps on a carpet) - Previously (pre-mid-1980's), could not individualize a sample - Could only indicates a strong personality - Introductions of deoxyribonucleic acid, or DNA - DNA extracted from body fluid evidence (often blood, seminal fluid, and saliva) Slide 2: Background to DNA: What is it? - Human body composed of trillions of cells - Inside almost every cell is a nucleus (contains structures known as chromosomes) - Nucleated cells have 46 chromosomes - 23 matching pairs -1 from mother, 1 from father - Chromosomes contain DNA - Thus, most cells contain DNA - Red blood cells do not contain DNA, white blood cells do contain DNA Slide 3: - DNA as a two-stranded molecule - Double helix - Compromised of chains of nucleotides - Sugar (deoxyribose) linked to phosphate, and - Base -Adenine (A) -Thymine (T) -Guanine (G) -Cytosine (C) - Hydrogen bonds between bases - Sequence of bases constitute our genetic code Slide 4: - Two kinds of DNA: 1\. Nuclear DNA: - Found in nucleus of cells - One copy per cell - Equal contribution from each parent - Unique to the individual -Most valuable in criminal investigation 2\. Mitochondrial DNA (mtDNA) - Found in the mitochondria of each cell - Many copies within each cell - Transmission through **maternal** line - Not unique to the individual -Use more limited Slide 5: Uses of DNA Evidence - DNA has revolutionized identification procedures and criminal justice - DNA evidence may be used to: - Identify a single person as the donor (confirming the people who hadn't committed the crime), rule other people out) - More correctly, eliminates almost all others - Rule out a suspect as the donor - Link a perpetrator to multiple offences - Identify the victim - Through DNA of close relatives Slide 6: Identification and Documentation of Bodily Fluids at the Crime Scene - Samples taken from a victim or suspect are biological samples - Samples taken from the crime scene may not be - E.g. stain on carpet: blood, wine, oil? - Presumptive tests tell crime scene investigators: - Whether a sample is a certain substance - That a substance is not a certain substance - Highlight an area that warrants further investigation -Prioritize areas for processing (search for actual evidence that's there) Slide 7: - Positive reaction from presumptive test must be subject to confirmatory test - May give false positive - Confirmatory tests performed by forensic biologists at a forensic laboratory - More timely - More expensive - More specific (done in lab) -Further rests may be required for individualized (cannot be done in an hour, CSI effect) Slide 8: Presumptive Tests for Blood - Presumptive tests for blood: - Colour spot tests -Rely on properties of hemoglobin -Hemoglobin: oxygen carrying molecule found in blood - Sensitive - Easy to perform Slide 9: - Guidelines for presumptive testing of blood at the crime scene: - Ensure sufficient samples available - **Never place chemical on the stain** -Rather utilize sterile swab or filter paper (chemical goes on swab, not stain, If you put on sample, can contaminate) - Positive and negative controls - Thorough documentation -Location -Date and time -Name of the CSI -Which test(s) performed -Lot number and expiration of chemicals Slide 10: Luminol - Sprayed and viewed using special light sources - Reacts to iron (heme) in blood - Will fluoresce -Done through a process called chemiluminescence (blood reacting to chemical) - Advantages: - Highly sensitive (can detect blood diluted 100 thousand times) - Does not interfere with DNA testing - Disadvantages: - Requires complete darkness - Faint luminescence - False positive to substances containing iron - Slide 11: Bluestar - Developed to overcome problems with luminol - Most crime scene investigators now prefer BLUESTAR - Advantages over luminol include: - Non-toxic - Total darkness not required - Stronger luminescence - Longer lasting reaction - Higher sensitivity - Also does not interfere with DNA analysis Slide 12: Hemastix - Originally to test presence of blood in urine - Colour change from 0-6 - 6= indicates presence of blood - Disadvantages: - Interferes with DNA samples - False positives with rust, bleach, and vegetable extracts Slide 13: Phenolphthalein (Kastle-Meyer) - Conducted on filter paper or swabs (a drop of reagent is placed on swab + a drop of hydrogen peroxide) - Reagent utilized with hydrogen peroxide - Colour change: - Pink in presence of blood - Disadvantages: - Interferes with DNA analysis -Do not test the stain itself -Swab stain, test swab - False positives: horseradish and potatoes Slide 14: Presumptive Tests for Seminal Fluid: Acid Phosphate (AP) Colour Test - Utilized with alternate light sources - Seminal fluid will fluoresce under certain wavelengths of light - Once located, perform presumptive tests - Acid Phosphatase (AP) Colour Test ("Fast Blue Test") -Acid phosphate: enzyme secreted by the prostate gland into seminal fluid -Test reacts to presence of acid phosphate -Swab stain with clean, sterile swab or filter paper, apply reagent -Purple indicates probable presence of semen -True positive in 30 seconds -Recorded as negative if no colour change within 2 minutes - False positives with other bodily fluids, fungi, and contraceptive creams Slide 15: Presumptive Tests for Saliva - No test that is specific for saliva - DNA obtained from skin cells with saliva - Not the saliva itself, skin cells in the mouth - Generally, area of suspected deposition tested - Swabbed using dry, sterile swab - Bite marks: -Moisten swab with distilled or sterile, deionized water and run over suspected bite wound -Follow with dry, sterile swab for collection (ex. can collect from chewing gum, cigarette butts) Slide 16: Collection of Body Fluids at the Crime Scene - Body fluids at the crime scene may be: - \(i) Liquid state -Wet body fluid stains -Place sterile swab or filter paper into still-liquid sample and allow it to be fully saturated -Air-dry and preserve in paper envelope or paper evidence bag -If not permissible may use plastic bag for transportation purposes -don't put wet things in plastic bags as they can mould, though it may not be permissible - \(ii) Dry state -**More common** in crime scene investigation contexts -Cut out stain or scrape stain into sterile filter paper (might use an exacto knife to cut out a stain from the carpet, or perhaps scrap the evidence) -To swab a dry stain: -Moisten swab with distilled or sterile, deionized water -Follow with dry swab for collection Slide 17: Preservation of Body Fluids - Storage of body fluids in airtight or warm environments accelerates deterioration - Body fluids evidence should be: - Air dried at room temperature - Packaged loosely in paper evidence bag - Thoroughly documented: -Name or initials of individual collecting evidence -Date of item collection and transfer -Agency, case number, crime type -Storage location -Brief description (ex. blood swab from living room area) - Packaged with biohazard label (body fluid evidence, must wear appropriate PPE for opening bag) Slide 18: Analysis of DNA and Body Fluids in the Lab - Recall: - Evidence in Canada: -Case receipt\> Evidence Recovery Unit\> Forensic Biology Unit -Centre - Forensic biologist analyzes biological materials - DNA is extracted from body fluids and analyzed - Confirmatory testing must be performed prior to DNA analysis -Tell us that the substance is definitely body fluid evidence Slide 19: Confirmatory Tests 1\. Blood: - Hemochromagen chemical test -No false positives - Teichmann test - Takayama test - Once confirmed as blood, precipitin tests differentiate between animal and human - Further tests for individualization 2\. Seminal Fluid: - Microscopic examination for spermatozoa -Staining techniques to assist in visualization -Differentiate sperm cells from extraneous material \- Further tests for individualization 3\. Saliva: - No specific tests - Previously tested for presence of amylase -Enzyme present in saliva and other body fluids Slide 20: DNA Analysis - Sir Alec Jeffreys (1950-present) - First successful use of DNA for identification - "DNA fingerprinting" - Results rendered as bar code - Disadvantages: -Timely (approximately 6-8 weeks) -Expensive -Sample must be substantial -Does not allow for analysis with older or degraded stains -Have to keep enough of sample for the defense to test as well in a court of law Slide 21: - DNA typing - DNA extracted from body fluid evidence -Chemical procedures break down cell to obtain DNA in the nucleus - DNA amplified -Amplification makes millions of DNA copies - Separation of DNA fragments by size - DNA profile based on size of each fragment copied - DNA profiles compared to reference -Suspect, victim, other evidence, or a database Slide 22: - DNA typing advantageous because: - Relatively inexpensive - Allows for DNA analysis with old or degraded samples - Allows for DNA analysis with small samples -Owing to amplification - Timelier - Generally, DNA profile developed within 2 days Slide 23: CODIS: The DNA Database: - DNA profiles entered into CODIS - Compared with victim -Elimination purposes - Compared with possible suspects - 4 local investigative indices (2013): - Ottawa, Regina, Edmonton, Vancouver - Also: -Center of Forensic sceinces, and -Laboratoire de sciences ju Slide 24: National DNA Data Bank (NDDB) - After entered in CODIS, profile entered in NDDB - Maintained in Canada - NDDB includes: - Convicted Offender Index (COI) -DNA profiles collected from convicted from crime scene investigations - Crime Scene Index (CSI) -DNA profiles obtained from crime scene investigations - If no matches, profile maintained in NDDB Slide 25: Interpretation of Results: What does a "DNA match" mean? - Common assumption that forensic science is infallible - -Meaning of "match" may be exaggerated - Estimation of how common or rare a DNA profile is, is based on relevant statistics: - Step 1: Assume suspect does not have an identical twin - Step 2: Perform random match probability -In Canada, fully matched profile consists of 20 locations (short tandem repeats: STR's) on the DNA -Extremely variable among individuals -Indicates chance that someone unrelated to the defendant matches the DNA -E.g.; "Chance of this DNA profile occurring in someone other than the suspect is 1 in 100 trillion" - Indicates probability, not certainty **Lecture 8A-Week 10: Fingerprint Evidence** Slide 1: Introduction to Fingerprints - Universally accepted as positive method of identification - Not junk science, it is accepted - Dactyloscopy (fingerprint identification) - Comparison of impressions made by fiction skin ridges - Two important scientific axioms: - Every fingerprint is unique -Between individuals -Within an individual, from digit to digit - Fingerprints do not change throughout life -Unless damage to dermal skin Slide 2: Fingerprints: What Are They? - Skin has two mains layers: - Epidermis (outer layer) - Dermis (inner layer) - 5% of human skin area= raised ridges - "Fiction ridges" -Formed during development in utero - Friction ridges function to: - Create friction - Heighten sense of touch - Allow skin to cool by discharge sweat -Raise eccrine (sweat) gland ducts Slide 3: - Sweat from friction ridges transfer onto surface - Creates the fingerprint - Fingerprint residue - Composition of inorganic and organic substances -99% water -Also: amino acids, proteins, glucose - Fingerprint examination only possible due to secretions - Fingerprint development mediums react with substances in fingerprints residue Slide 4: Fingerprint Patterns - Friction skin arranged to form certain patterns - Use terminology: - Delta: -Ridges converge from three directions - Core: -Inner most portion of fingerprint pattern - Recurving ridge: -Any fingerprint ridge that retraces its course Slide 5: - Three basic fingerprints patterns: - Loop: -Most common -Approximately 60-65% of population - Whorl - Arch: -Least common -Approximately 5% of population - Within these major classes, fingerprint examiners recognize other classifications Slide 6: - Loop: - Radial: -Loop flows towards thumb -Ridge enters from thumb side -Ridge recurves to exit on little finger side -One delta - Ulnar Loop (think to pinkie and ring finger make a "U", ulna bone there) -Loop flows towards little finger -Ridge enter from little finger side -Recurves to exit on little finger side -One delta Slide 7: - Whorl - Plain Whorl: -1+ recurving ridges, 2 deltas -Straight line between deltas bisect ridge(s) at core - Central Pocket Loop: -1+ recurving ridges, 2 deltas -Straight line between deltas does not bisect - Double Loop: -2 loops formations (separate and apart) - Accidental: -Non-specific; 2 deltas -Upthrust: ridge flow unusual, in upward direction Slide 8: - Arch: - Plain Arch: -Ridges run in one side, out the other -Smooth, arching formation -No delta - Tented Arch: -Ridges run in one side, out the other -Upthrust in middle -Appearance of tent - No delta Slide 9: - Once pattern type and classification determined, friction ridges examined for minutiae - Minutiae: unique variations/sub patterns -Short ridges -Splitting ridges (bifurcations) -Dot -Ending ridge (ability to follow ridge back to it's start) -Crossover -Island -Two bifurcations facing each other - Arrangement of minutiae allow positive identification Slide 10: - Three types of fingerprints - \(i) Latent -Require development for visualization -Most common at crime scene - \(ii) Visible -Also known as 'patent fingerprints" -Clearly visible -Left when friction ridges coated with a substance that is transferred, or fingerprint left in visible medium - \(iii) Plastic -Also known as 'indented fingerprints' or 'impression fingerprints' -Clearly visible -Left when one presses into a material and leaves an impression Slide 11: Identification of Latent Fingerprints at the Crime Scene - Identification of visible or plastic fingerprints easy because both are visible - Latent fingerprints require development - Technique determined by substrate - Porous: absorbs fingerprint secretion -e.g. cotton, paper, unpainted wood - Non-porous: impermeable substrate -Print captured on surface -e.g. glass, metal, plastic Slide 12: Alternate Light Sources - High-intensity light that emits visible and invisible light beams to locate fingerprints - Organic materials can be made to fluoresce - Used with various filters - Always wear safety goggles - Increase likelihood of identification by continually altering angle of light source (lie down and look at your floor, can see more dirt, dust, hair, a lost earring perhaps) - Once latent print identified, photograph using white light - At oblique angle - Once a fingerprint is collected, it's gone Slide 13: Fingerprint Powder - Used as a method of: - Developing latent prints that have been identified with an alternate light source, and - Searching for latent prints -Based on contextual information and/or logic - Visualization by contrast (choose a powder of a different colour if need be) - Advantages: - Allows for lifting of the fingerprint -Preservation of the fingerprint as physical evidence - Inexpensive - Fast - Convenient Slide 14: Fingerprint Powder Types - Granular - Large, spherical grains which adhere to secretions - Not designed for lifting - Application: -Animal hair brush -Gentle brushing motion - Works best on: -Lightly grained surfaces -Surfaces that may be damaged by lifting - Flake: - Aluminum, gold, bronze - Designed for lifting - Application: -Zephyr brush -Twirling motion - Works best on: -Smooth surfaces -Non-porous surfaces - Magnetic: - Contain iron - Designed for lifting - Application: -Magnetic wand -Granular or flake - Works best on: -Articles such as magazines or paper Slide 15: - Powder choice made on basis of its ability to: - Adhered to fingerprint ridges - Not adhered to the substrate (being able to life a print without damaging a substrate) - Provide contrast -Between ridges and substrate Slide 16: Documentation of Fingerprint Evidence - All fingerprints must be photographed before collection because: - Shows location and direction of fingerprint in situ (situ= means as it is in the crime scene) - Records most complete detail - Fingerprints may be damaged/degraded during collection - Records laterality of fingerprint -I.e., if from left hand or right hand - Eliminates suggestion of forgery transfer Slide 17: - Fingerprint evidence should be photographed: - 1:1 in real size - With a scale ruler included - With a label that includes: -Crime scene investigators name or initials -Fingerprint numbers -Date - Using black and white film (provides the most contrast, but depends on agency) -Depending on the agency Slide 18: Preservation and Collection - Visible or plastic fingerprints in materials that are hardened or able to withstand transport may be sent to laboratory for collection and analysis - Methods of latent fingerprint preservation include: - Photography - Lifting -Apply fingerprint tape, smooth air bubbles, lift tape, place on blank card -Curved surfaces: gelatin or rubber lifting material (ex. doorknobs), can look like silly putty Slide 19: Analysis and Interpretation of Results - Once a fingerprint is collected it becomes physical evidence ("evidentiary print") - ACE-V - Analyze -Assess minutiae that may assist in possible identification - Compare -Compare evidentiary print with reference points - Evaluate -Assessing value of the unique characteristics -Forming conclusion - Verify -Peer-review to minimize the possibility of a misidentification Slide 20: - Fingerprints examiner may form one of three conclusions: - \(1) Individualization -I.e., the suspect made this print - \(2) Elimination -I.e., the suspect could not have made this print - \(3) **Insufficient detail for evaluation (CSI Effect-the idea that every print we identify is perfect)** Slide 21: Automated Fingerprint Identification System (AFIS) - Computerized fingerprint record comparison system - In Canada, evidentiary prints loaded into AFIS program to search for possible matches - If generated, fingerprint examiner must manually confirm the "match" -Checking that a number of points are identical on both the evidentiary print and the reference print -Allows linkage Slide 22: What Does a "Match" Mean? - How many points must we look at to confirm that prints are individualizing (or not)? - Previously, required 16 different minutiae points to match - International Association for Identification (IAI) (1995) determined: -"No scientific bases extents for requiring that a predetermined minimum number of friction ridge features must be present in two impression in order to establish a positive identification." - Fingerprint examiners now take holistic approach - Based on examiner experience and assessment of two sets of fingerprints as a whole -Utilize the verification process as confirmation for an identification **Lecture 8B-Week 10: Trace and Impression Evidence** Slide 1: Introduction to Trace - Edmond Locard (1877-1966) -"When any objects come into contact, there is always a transference of material from each object onto another" (Nafte and Dalrymple, 2016) - Basis for studying trace evidence - But the absence of trace evidence does not indicate that no contact occurred -"Any real evidence that must be extracted from another substance or items and is in very small amounts" Slide 2: - Generic term for microscopic materials - But more than this... - Analysis may be qualitative or quantitative - Usually unable to indicate specific source or origin - Trace evidence as class evidence - Trace evidence may include: - Gunshot powder residue - Rust - Wood or metal shavings - Garbage bags - And more! Slide 3: Identification and Documentation of Trace Evidence - As trace evidence is often small or microscopic, identification difficult - To assist in locating trace evidence: - Alternate light sources - Contextual information -Trace evidence often found in/on: -Clothing -Footwear -Suspect or victim -Tools and/or weapons -Vehicles Slide 4: - Regular documentation guidelines apply - Remember: - Document the location in detail - Photograph with and without evidence markers and scales - Always photograph before collection -Trace evidence should not be removed from clothing, footwear, or items able to be transported to the forensic laboratory -Submit entire item - Maintain Chain of Custody Slide 5: Types of Trace Evidence-Hair - Hair often recovered from crime scene, victims, suspects, other evidence - Generally associated with crimes involving physical contact - -Homicide, sexual assault, traffic accidents (typically physical) - Microscopic hair examinations as junk science - Does not "*have the capacity to consistently, and with a high degree of certainty, demonstration a connection between evidence and a specific individual or source"* - Only way that human hair can be linked to a specific individual or source is through DNA - If skin materials attached to hair root: nuclear DNA - If no hair root present: mitochondrial DNA (mtDNA) Slide 6: - May be probative value in microscopic hair examinations nonetheless: - Investigative leads -Species (animals or human) -Colour and texture of hair -Location of growth on body (head hair or pubic hair) -Hair treatment -Hair disease -Fell out naturally or pulled out Slide 7: Types of Trace Evidence-Fibers - May become evidence in a variety of cases - Homicide where victim is tied up, burglary where jacket got torn at the scene, and more\... - Fibers can be divided into: - Natural -Animals (wool, silk) -Plants (flax, cotton) - Synthetic (man-made) -Examples: -Polyester -Nylon Slide 8: - Whole textile fragments may yield individual characteristics - E.g., if torn may be able to fit together - Single fiber strands cannot be linked to a single source - Mass-production of garments and textiles means single fiber strands have low evidentiary value - May only examine class characteristics -Colour -Striations on the fibers -Cross-sectional shapes Slide 9: Collection and Preservation: Hair and Fibers - May be recovered using: - Disposable tweezers or forceps -Avoid cross-contamination if not disposable - Lifting techniques -Place adhesive side of tape onto the hair -Place tape in a sheet of clear plastic or fold - Paper druggist fold - Secure in polythene evidence bag and label - Method of recovery depends on scene conditions and case circumstances Slide 10: - Additional collection guidelines: - If trace evidence is on some moveable item, collect entire items and transport to forensic laboratory - Trace evidence on clothing: - Place sheets of clean paper between clothing layers and on top - Loosely fold or roll surface of trace inward - Secure and seal in paper bag - Air-dry if required, where possible - Package all evidence and samples independently Slide 11: Types of Trace Evidence-Glass - Wide-range of uses= revered often - Burglaries, assaults, and traffic accidents - Glass fractures in a predictable way - Radial cracks: fracture lines that run outwards from the point of impact (radial= radiates like sun) - Concentric cracks: link edges to radial cracks (concentric= connects) -Displace small pieces of glass up to 3m back towards the object/person breaking the glass Slide 12: - May link suspect to crime scene - Generally, only yields class characteristics - Colour - Chemical composition -E.g., Window glass: sodium, calcium silicate (\~70% silica and small amounts of other metallic oxides) - Thickness - Density - If compared to a sample from a sample from a suspect or a scene, still cannot link to a specific source because glass is often mass-produced - Large fragments may allow reproduction of fracture patterns or matching to source Slide 13: Collection and Preservation-Glass - Collect a representative control sample - Recover from the area of damage - Mark either the inside or outside surface to distinguish the two -Replication of fracture patterns (later) - Package all independently - If trace evidence is on some moveable item, collect entire item and transport to forensic laboratory - Clothing and footwear always in paper bags, if wet air-dry before you put them in - Package in solid containers Slide 14: Types of Trace Evidence-Soil - Soil is made up of mixture of: - Air - Water - Minerals - Decomposed organic materials (acorn fibers decomposing leaves) - Also, may contain contaminants such as pollen, fertilizers, or plant fragments - May be divided (broadly) into: - Sand - Silt - Clay Slide 15: - Class characteristics examined include: - Particle size -Sand: up to 2 mm diameter -Silt: less than 0.06 mm diameter -Clay: less than 0.002 mm diameter - Density - Chemical composition - Colour - Additional contaminants may allow links between suspects, victims, crime scenes - E.g., pollen, diesel, etc. Slide 16: Collection and Preservation-Soil - Collect a representative control sample - 1 tablespoon from the surface layer (ex. 1 tablespoon of dirt) - Package in an EPA-certified, sterile container - Package all evidence and samples independently - If trace evidence is on some moveable item, collect entire item and transport to forensic laboratory - Do not attempt to dislodge soil from footwear - Clothing and footwear always in paper bags Slide 17: Types of Trace Evidence-Paint - May be used to protect or decorate surfaces - In many cases is applied in multiple layers -Motor vehicles usually have 4 layers of paint - Commonly recovered in traffic accidents and forced entry cases - Generally, only yields class characteristics - Generally, only yields class characteristics: - Colour - Layering - Weathering and texture - Chemical properties (solubility and composition) - If large fragments recovered, may allow for matching to a single source, but often fragments that are recovered are too small Slide 18: Collection and Preservation-Paint - Collect a representative control sample - Recover from the area of damage - If recovering for control sample, obtain all layers to base surface - Packaging all evidence and samples independently - If trace evidence is on some moveable item, collect entire item and transport to forensic laboratory - Clothing and footwear always in paper bags - Package in paper (druggist fold) and seal in polythene evidence bag - Never use lifting technique on paint - If paint chip is large enough to allow a physical match to the source, package in rigid container Slide 19: Analysis and Interpretation of Trace Evidence - Trace evidence analyzed in the forensic chemistry unit - Centre of forensic sciences no longer performs soil analysis - Steps of analysis: - \(1) Qualitative analysis; determine what the substance is -May utilize tests to determine and analyze different components of a substance -Chromatography and spectrometry -For example: gasoline or engine oil? Nylon or Raylon? - \(2) Quantitative analysis of chemical constituents, percentage of each component -For example: Esso versus Shell and batch, and where batch was sold - When a substance is identified, significance must be determined Slide 20: - Trace evidence generally only allows linkage to a group or class - Often not able to link to a single or specific source - Class characteristics may high or low significance - Significance of class evidence may be increased if parent population is small (i.e. if the class itself is rare) -Even then, still not individualizing in the same way as DNA or fingerprint evidence - Significance of trace evidence depends on the size of the parent population -Duty of the examiner to be clear, transparent, and explicit in the significance of the evidence - Databases may assist in the analysis and interpretation of trace evidence Slide 21: Misconceptions and the CSI Effect - Databases for trace evidence in Canada: - Paint Data Query (PDQ) -Maintained by Royal Canadian Mounted Police -Contains chemical compositions of paint from cars marked in North America after 1973 -Provides: -Most likely manufacturing plant -Make/model of vehicle -Year range for vehicle paint came from -Limitation: manufacturers may not be willing to divulge the paint compositions they use Slide 22: - Also are some commercially available databases that assist in trace evidence analysis - None offer individualizing - Overall, list of databases resources not as exhaustive as is represented in popular media - Unrealistic portrayal of some omniscient database that allows analyses in seconds -CSI effect Slide 23: Introduction to Impressive Evidence - Occurs as a result of physical contact between an object and a substrate - Impression evidence may include: - Fingerprints and palmprints - Nose prints - Ear prints - Toolmarks - Footwear - Tire impression Slide 24: Footwear Evidence - Offenders will always leave footwear marks; we deposit materials onto substates as we walk - Two forms: - Two-dimensional (print) -Made on non-giving surfaces -Dimensions of length and width, not depth -Latent or visible - Three-dimensional (impression) - Remain after show has become embedded on soft surface - Dimensions of length, width, and depth - Quality of impression depends on the composition of substrate, amount of moisture, presence of contaminants in substrate (sticks, stones, other debts) Slide 25: Tire Evidence - Tire prints/impression reflect tread design and features of individual tires - Important terminology: - Tire treads: composed of many tread blocks -Tread blocks are arranged to form patterns and separated by grooves - Wear bars: raised areas in tire grooves -Raised 2/3" above based of tire grooves -Indicate tire should be changed -Tire **impression becomes a print** when tried tread is worn top remaining 2/3" depth Slide 26: Importance of Impression Evidence - Physical characteristics may be used to provide: - Investigative leads - Identify or eliminate a specific shoe or tire from having made the print or impression - Footwear and tire evidence may also assist in: - Determining number of suspects/vehicles involved - Determine paths to/from a crime scene - Ascertaining sequence of events -Directionality, movement through crime scene - Identify links between crime scenes - In addition, footwear evidence may indicate gait characteristics: -Step, length, and width, speed Slide 27: Identification and Documentation of Impression Evidence - Not always be visible - Caution - May be identified by: - Thinking critically - Utilizing a light source -White light or flashlight at oblique angle -Alternate light source - After identification, must assess whether prints/impressions are of evidentiary value - Eliminate irrelevant prints and impressions Slide 28: - Follow regular documentation procedures - Detailed note taking is critical -Location and description - Quality photography critical in circumstances in which collection and preservation not possible - Oblique lighting may be used to enhance detail - Camera should be mounted on tripod, positioned perpendicular to the print or impression - Scale should be level with impressions that have significant depth Slide 29: Enhancing Details - May be required for photography or collection - Two-dimensional prints: - Enhancement with fingerprint powder - Enhancement with other chemicals -Blood: luminol, BLUESTAR -Soil: -Potassium thiocyanate: reacts with iron (orange/red) -Bromophenol blue: reacts with pH levels (blue) - Three-dimensional prints: - Snow Print Wax - Dark coloured aerosol paint Slide 30: Collection and Preservation of Impression Evidence - If located on surface that is easily transportable, should be collected and preserved as a whole and submitted to the forensic laboratory - Most scenarios do not allow this - Only collect evidence after all documentation is completed - If two-dimensional print: lifting - If three-dimensional: casting Slide 31: Lifting Techniques - Electrostatic lifting - Uses a high-voltage power source to create static charge - Enables transfer of dry origin print from surface to black lifting film -Dry origin print: does not have tight bond with substrate -E.g. Walk across dirty floor and step onto clean tile - Advantage: evidence will not be harmed if unsuccessful -Print remains intact - If electrostatic lifting is unsuccessful, other methods of enhancement and lifting may be used: - Enhancement with fingerprint powder or chemicals - Lifting with adhesive or gelatin lifter Slide 32: Casting Techniques - All impression evidence should be collected using casting techniques - Creates a three-dimensional cast which may be suitable for parison purposes - Steps for casting impression evidence: - \(1) Fill plastic/Ziploc bag with 1.5 kg dry dental stone powder - \(2) Add water and mix until pancake-batter consistency achieved - \(3) Pour mixture into impression slowly - \(4) Spread mixture gently, to ensure impression void of air pockets - \(5) Allow to cure -Dependent on scene conditions and impression contexts (20-45 minutes) - \(6) Remove excess substrate with water and soft bristle brush after 48 hours Slide 33: Casting Impression Evidence in Snow - Two methods: - \(1) Snow Print Wax and Casting -Insulates against exothermic reaction generated during curing of dental stone - \(2) Casting with Sulfur -Steps are similar as casting with dental stone: -(i) 1.5 kg powder sulfur heated -(ii) Liquifies at approx. 116 degrees Celsius and darkens (yellow to amber) as it melts -(iii) Remove from heat when fully liquid -(iv) Allow to cool until crystallization at edge and liquid thickens -(v) Pour into impression Slide 34: Class Vs. Individual Characteristics - Analysis of footwear and impression evidence generally examined macroscopically and then microscopically - Examination of class characteristics followed by examination of individual characteristics - Recall: physical evidence cannot always be linked or related to a common origin with high degree of certainty - Often only associated with a group or class Slide 35: Class vs. Individual Characteristics - Footwear evidence - Class characteristic -Type of footwear -Tread pattern -Wear patterns -Size -Defect's indicative of manufacturing process - Individual Characteristics -Tears -Cuts -Foreign materials embedded in the tread - Tire evidence - Class characteristic -Tire dimensions -Tread pattern -Wear pattern -Tire tracks: type of vehicle (track width, wheelbase, turning diameter) - Individual Characteristics -Tears -Cuts -Foreign materials embedded in the tread Slide 36: - Shoeprint Image Capture and Retrieval (SICAR) - Incorporates multiple, commercial databases: - TreadMark -Uses footwear pattern, size, damage, and wear to identify individual prints or impressions -Footwear evidence from crime scenes inputted -Compared with footwear data from suspects in custody and crime scenes -Match may yield name, date of birth, criminal record number, and places of similar offences for possible suspects - SoleMate -Contains information on specific print or impression patterns -Manufacturers, date of market release, image of footwear sole pattern -Limitation: manufacturers may use same sole or sell molds to other companies Slide 37: - TreadMate used for tire evidence - Contains information on more than 5000 vehicle tire and tire tread patterns - Provides information on: - Manufacturer - Date of release - Pattern features - Images - Limitation: manufacturers may use the same tread - Difficult to find exact match or model Slide 38: - Databases may provide valuable investigative leads - Not able to definitively link to a single source - Class characteristics may have high or low significance - Individual characteristics may enhance significance - Examiner may provide one of the following conclusions: - \(i) The impression evidence "was" made by the shoe/tire - \(ii) The impression evidence "was probably" made by the shoe/tire - \(iii) The impression evidence "was possibly" made by the show/tire - \(iv) The impression evidence "was not" made by the shoe/tire - \(v) The impression lacks sufficient clear detail for any significant conclusion **LEC 9A-Week 11: Blood Spatter Evidence** Slide 1: Introduction to Blood Spatter Evidence - Analysis of blood performed in forensic laboratory - By a forensic scientist - DNA analysis -Who the blood originated from - However, analysis of blood spatter evidence or patterns of blood at the crime scene performed at the crime scene itself Slide 2: Introduction to Blood Spatter Evidence Slide 3: - Important because may: - Provide information that may be used to establish time of death - Corroborate or disconfirm other evidence -Statements from victims, witnesses, suspects - Reveal important investigative information -Where the assault happened -Position of victim, assailant, and other items -Type of weapon used and how much force was involved -Number of wounds -Movement through crime scene and the sequence of events -Possible alterations to the crime scene (talking about void patterns) Slide 4: - When a blood drop falls, it forms a sphere - Surface tension - Blood drop will not break unless: - Strikes a surface - Acted upon by some force - When blood drop breaks, it creates spatter - "Bloodstain pattern evidence" -Grouped on basis of: -Production -What they may tell a crime scene investigator Slide 5: Classification of Bloodstain Patterns - \(1) Passive stains - Caused when blood falls naturally due to gravity - \(2) Transfer stains - Caused when a person or object comes into contact with another object - \(3) Spatter stains - Caused when blood drops are propelled onto a surface by a force or energy - Patterns may form through each stain type Slide 6: Passive and Transfer Stains - Passive stains may produce: - \(i) Drip pattern -Formed when free-flowing blood drips from a stationary source (like a hand onto the floor) - Transfer stains may produce - Wipes, swipes, transfers, or contacts - \(i) Wipe pattern -Formed when a perpetrator attempts to wipe blood away - \(ii) Contact pattern -Formed when an item bearing blood leaves a contact pattern on a surface Slide 7: Spatter Stains - Spatter stains may produce: - \(i) Cast-off pattern -Formed when blood is propelled by force greater than gravity -Longer/lighter item increases cast-off owing to larger arc (5 inch knife vs. long hockey stick) - \(ii) Back spatter or forward spatter pattern -Gunshot wounds - \(iii) Arterial spurt pattern -Formed when blood spurts from body when arteries under pressure as a result of arterial damage (see this with sharp force trauma) -Results in series of "s", "v", or "w" shapes - \(iv) Expiration pattern -Formed when blood in respiratory system is expelled from mouth or nose by force Slide 8: Classification of Bloodstain Patterns - Important that the crime scene investigator looks for the absence of staining where such would normally be expected - Void pattern: F ormed when an item is removed from the area after a bloodstain has occurred Slide 9: Identification and Documentation of Blood Spatter Evidence - Most obvious, but some may require visualization - Alternate light sources - Magnification devices - Recall: two common methods of visualizing blood at a crime scene are: - Luminol and BLUESTAR forensic -Sprayed onto area and viewed with alternate light source -Do not interfere with subsequent DNA testing Slide 10: - Notetaking should be meticulous with particular attention to things such as: - Suspect or victim handedness (what hand did they use? Right or left?) - Physical descriptions -Injuries -Physical limitations - Conditions of the crime scene -Skeletonized stains: perimeter of stain has dried and center has flaked away leaving a visible outer ring - Presence of other fluids or substances - Enhancement methods utilized Slide 11: - Recall photography guidelines - Overall, mid-range, close-up - First set of all photos without scale and evidence marker, second set containing such - Plane of photograph parallel to surface -Utilize a tripod - Videography - Sketching - Elevation sketches may be required in addition to other sketches generated (usually we see blood spatter evidence on walls or ceilings, so this is helpful) Slide 12: - Measurements only be completed after all other documentation - Measurements as form of analysis - Take notes and photographs during this process - **Documentation efforts may be only form of preservation for blood spatter evidence (can't collect pattern)** - Blood itself should be collected and preserved per guidelines for blood evidence -Control samples Slide 13: Analysis and Interpretation of Blood Spatter Evidence - Based on observation and measurement of: - Location - Size - Shape - Number - May determine: - Directionality -Narrow end (tail) points in direction of travel - Point of conversion -"Area of origin" -Relative location of source of that blood Slide 14: - Method of analysis: stringing (think of *Dexter*) - Stretching pieces of string through number of bloodstains based on determination of direction from which they came and angle of landing - Measuring length and width of individual stains allows determination of angle of impact - Combination allows determination of how victim positioned at impact - Limitation: - Now have specialized computer software programs that may be used in combination with digital photography to allow for enhanced precision - Interpretation of blood spatter evidence somewhat [subjective] -Consider in conjunction with other types of evidence **LEC 9B-Week 11: Firearm and Toolmark Evidence** Slide 1: Introduction to Firearm and Toolmark Evidence - Firearm evidence - Performed by a **forensic scientist** (examiner) - Determination of whether a particular weapon fired a suspect bullet, cartridge, or other ammunition - Did one fire arm fire that specific bullet - Different than ballistics -Ballistics: study of path of trajectory or ordinance - Toolmark evidence - Performed by a forensic scientist (examiner) - Determination of whether a particular tool made a suspect tool mark - Tool: any hard object that makes an impression on a softer object (crowbar, knife) - Toolmark: the impressions, cut, gouge, or abrasion left by a tool (don't say "the knife did this", rather they say "the tool has done this"- keep language neutral) Slide 2: Firearms - Barrel: bar of steel with center drilled out - Drill removes center, leaves microscopic irregularities - Lands (used by forensic scientist in matching bullets to a specific firearm) - After barrel is produced, is drilled again with a broach cutter to produce rifling - Rifling: series of spiral grooves made in the barrel of gun to ensure bullet flies straight - When bullet travels through the barrel, becomes marked by lands and prial grooves - Striations -Class and individual characteristics Slide 3: - Class characteristic - Number of lands and grooves - Width of lands and grooves - Caliber (size) - Direction of rifling twist - Degree of twist - Allowing us to look broadly, to differentiate a rifle vs. a handgun (ex..22 caliber gun but the suspects gun's caliber doesn't match, we don't move forward) - Individual characteristics of bullets: - Microscopic irregularities along lengths of lands and grooves that are made during: -Manufacture -Subsequent use Slide 4: - Bullet is only part of a cartridge, which is what is expelled when shot - Cartridge consists of: - Cartridge case - Projectile (bullet) - Gunpowder - Primer -Ignites gunpowder, ejects projectile - Center-fire: primer stored at base - Rim-fire: primer store in rim Ex. a.22 caliber rifle has a rime fire, we can look at cartridge to determine class characteristics Slide 5: - Class characteristics of cartridge case: - Caliber (size) - Firing pin location - Relative location of the extractor - Primer type - Extractor and ejector marks - Firing pin size and shape - Breech face markings - Individual characteristics of cartridge case: - Microscopic irregularities along lengths of lands and grooves that are made during: -Initial manufacture -Subsequent use -Bullet tends to travel, cartridge falls to the ground Slide 6: Toolmarks - Tool mark evidence most often associated with property crime, but also found in homicides (ex. home invasion-window being pried open, can also occur during death investigations) - May be divided into: - Compression tool marks -"Impression tool marks" -Created when tool pressed into a softer object (ex. crowbar opening car window creates an impression into paint) -Most common - Striated tool marks -Created when a tool is impressed and moved (ex, cheese-knife impressions/striations, apple being bitten into-teeth marks) - One tool may produce different tool marks depending on what makes contact and how (imagine a big bread knife with the striations on it, think of the serrated part, if I stab someone you can see striations instead of using it to open something without moving it and leaving impressions) - Quality of tool arks dependent on substrate - Softer materials = higher quality tool marks (e.g., lead, copper, brass, plastic, paint surfaces)-this is a limitation Slide 7: - Class characteristics of toolmark evidence - Width of the tool (mark) (if a person is hit with a crowbar or a piece of wood) - Shape of the tool (mark) - Size of the tool (mark) - Individual characteristics of toolmark evidence: - Microscopic irregularities: -Manufacture -Subsequent use -Damage from misuse or general wear -Avoid individualizing (can't say it's a particular tool, but we can say it looks like a certain tool) Slide 8: Identification and Documentation Firearm and Toolmark Evidence - No enhancement or visualization - Recall: general documentation procedures - Importance of close-up photographs with respect to tool mark evidence overall, mid-range, closeup) - Importance of documenting location -After documenting position of evidence check for presence of other evidence: -Body fluid -Fingerprint -Trace -What side is the handle facing? NSEW? -Can infer or use linkage theory to infer where other latent evidence is, look at window pried open (visible evidence) and you may find fingerprints there too! Slide 9: - Additional document guidelines for firearm evidence: - Document position of cylinder and chamber - Open cylinder and photograph front and back of cylinder while in this position (normally can't touch evidence, but to ensure safety, must check if gun is dangerous or going to go off-doesn't mean you move it, but more so check if it's loaded) - Remove cartridges and photograph before and after cartridge removed - In order that they were loaded in the firearm -May be required to physically number each, near the mouth -If bullet, mark on base - Document if serial number defaced (Forensic identification officer should mark that down, to save in our notes, was defaced and didn't become defaced during transport) - Where applicable, document: -Position of safety of the firearm -Position of hammer, bolt, and/or striker Slide 10: Collection and Preservation Firearm Evidence - Treat all firearms evidence as loaded - Removed ammunition before packaging - If bullet embedded in substrate: - Collect item, if feasible - Never dislodge bullet with hard or sharp object (never use something like tweezers to dislodge bullet) - Bullet, cartridge, cartridge case: - Wrap in sterile paper or polythene evidence bag - Place in rigid container - All evidence with ammunition labelled "LIVE AMMUNITION" in caps lock and sharpie Slide 11: - Firearms: - Packaged in cardboard box, secured with plastic ties (called "gun boxes") - Where possible, secure cylinder in open position - -Pistol: slide locked back and open - If blood on firearm evidence, use biohazard label - All evidence packaged individually - All evidence packaged in protective materials - To preserve fingerprint evidence and/or trace evidence - Articles of clothing that may possess gunshot reside packaged according to previous guidelines Slide 12: Collection and Preservation of Toolmark Evidence - First, examine for trace evidence - Cast toolmark evidence - Allows for comparisons between toolmark evidence and any suspect tool(s) -Suspect tool should never be placed into a tool mark for comparison (never alter original mark) - Use a silicone rubber material as a casting agent - Following casting, collect entire item or portion of item for analysis - Not always feasible Slide 13: Analysis and Interpretation of Results - Performed in forensic laboratory - Firearm and toolmark examiner - Examination of firearm, ammunition, tool, or tool-mark, and physical matching to a suspect weapon or tool - E.g., Bullet to a specific firearm, Tool mark to a suspected knife (based on physical matching) - Examination of class characteristics first, then individual characteristics - Class characteristics place evidence into group of firearms or group of tools - Individual characteristics indicate the evidence came from a specific firearm or was made by a specific tool (to the exclusion of all others, knife, toolbar) -**CSI EFFECT: forensic science is infallible, evidence is plentiful** Slide 14: Analyzing Toolmark Evidence - If no suspect tool has been submitted, examine class characteristics may provide investigative leads - If suspect tool has been submitted: - Examine class characteristics -If consistent between suspect tool and toolmark evidence, will use the tool to prepare test toolmarks - Microscopic comparisons require: -Test toolmark and toolmark evidence made on same substrate -Test toolmark and toolmark evidence made with same angle of attack Slide 15: - Microscopic comparisons of test toolmark and toolmark evidence from the crime scene performed to match individual characteristics - Comparison (compound) microscope - Allows comparison of two objects as one image - Look at unknown (test mark) before known (toolmark evidence) to avoid bias (usually placed on right hand side of compound microscopic) - To make a positive identification, both class and individual characteristics must match - 7-8 minimum Slide 16: Analyzing Firearm Evidence - Goal of initial examination of fired bullet or cartridge case: determination of general rifling characteristics - Narrow make and model of firearm that may have fired bullet/ejected cartridge case - Class characteristics - Macroscopic and microscopic methods - May use micrometer -E.g., to determine caliber of a fired bullet - Class characteristics may be used to search database(s) for matching firearm makes/models Slide 17: Canadian Integrated Ballistics Identification Network (CIBIN) - Partnership between major forensic labs - RCMP Forensic Science & Identification Services - Centre of Forensic Sciences - Quebec Laboratoire de Sciences judiciaires et de medicine legale - Digitized images of bullets and cartridges cases from crime scenes - Allows search for matches to other crimes and known weapons (a gun found in a river can be a crime scene, and this cold case may assist a future crime scene) - -Presumptive (Screening) test - Requires confirmatory testing using microscope Slide 18: Physical Matching - When suspect firearm obtained: - Examine class characteristics for consistency - Must be test fired to obtain comparative test bullets/cartridge cases (put new bullet into suspect's firearm) -Ensure firearm mechanism operational and safe (is the serial number defaced?) - Utilize comparison (compound) microscope - Search for distinctive patterns of parallel striations that match -3+ consecutive striations for positive identification - Look at unknown (test bullet/cartridges) before known (firearm evidence) to avoid bias Slide 19: Conclusions - The firearm and toolmark examiner may reach one of the following conclusions: - \(1) Positive Identification -Class and individual characteristic match -Firearm evidence: 3+ consecutive striations match -Toolmark evidence: 7-8 matches - \(2) Negative identification -Class and individual characteristics do not match (suspect firearm or suspect tool is excluded) - \(3) Inconclusive (doesn't mean not useful) -Class characteristics match but the individual characteristics do not -Individual characteristics may have altered by further use between time of use and collection as evidence - \(4) Unsuitable for identification purpose **Week 12 Lecture 10A:** Slide 1: Defining a Question Document - "Anything that contains letters, numbers, or any type of symbol that could express meaning to another person, and whose authorship or authenticity is in doubt." Slide 2: Intro to Document Evidence - Questioned document examiners responsible for: - Comparing handwriting samples - Examining methods of document creation - Examining alter or damaged documents - Important: as it may: - Identify author or source - Yield information (suspects, victims, and/or locations) - Prove or disprove an alibi - Provide other investigative leads Slide 3: Examination of Handwriting - Questioned document examiner - Scientific comparison and analysis of a documents - Studies physical characteristics to infer document source or authorship and document alteration - Scientific base - Commonly accepted - Graphology - Study of handwriting to determine a person's personality - Studies physical characteristics to infer information surrounding personality or behavioural profiling - No scientific base - Use debated - Use of graphology is not scientifically based because it is subjective Slide 4: - Children learning to write: letter formation - The idea of letter formations where children often copy from a copy book or following examples from teachers. Therefore, all children have similar writing styles - Basic writing styles is a class characteristics - Shift to writing whole words and sentences, eventually focusing on content rather than letter formation (writing as a semiconscious/conscious habit) - When we begin to write at a lower consciousness, we form individual characteristics in handwriting Slide 5: - Individualization owed to differences in: - Visual perception - Neurotransmitter coordination - By adulthood, handwriting is unique (individualized) - Factors that may affect handwriting include: - Illness oh physical challenge - Illicit use of drugs or alcohol - Visual impairment - Extrinsic factors (e.g. position, surface, tool) Slide 6: Altered Documents - Addition of something after original production - Obvious and discernible evidence of a second writing instrument may prove alteration (ink differentiation, differ ink= different chemical constituents) - Crime scene investigators should be aware that document damage does not always impeded analysis - May be restored in some cases Slide 7: Identification and Documentation of Document Evidence - General principals of documentation apply - Note-taking -Note take location in relation to other items. Also what does the scene tell us? - Sketching and mapping (same regulations) - Photography -Recall general photography guidelines and sequence of photography Quality photographs may form basis for analysis where document evidence cannot be collected - Videography (same regulations) Slide 8: Collection and Presentation of Document Evidence - Process items of physical evidence such as document production tools per usual guidelines - Paper documents: - White cotton gloves over latex or nitrites - Preserve as found - Package in sterile, acid-free paper evidence bag -Plastic may create moisture - Label appropriately - Label charred domestic documents: spray with fine mist of clear varnish, packing in a box with loose cotton - Label wet soaked documents: - Preserve through freezing Slide 9: Collection of Writing Standards - Handwriting analysis as comparative - Exemplar: - Collected exemplar from the crime scene - Requested exemplar -Requested by warrant and written under supervision of a sworn police officer at the station -Not the responsibility of the crime scene investigator Slide 10: Collection of Writing Standards - Collected exemplar: - Pro: likely to be undisguised, range of variation - Con: authorship may be congested, may not allow like to like comparisons, does not duplicate the questioned documents - Requested exemplar: - Pro: authorship known, allows like to like comparisons - Con: may be disguised, may be nervous under warrant and thus writing may be impacted, limited range of variation Slide 11: Analysis and Interpretation of Document Evidence - May require other evidence processing upon arrival at the forensic laboratory (e.g. fingerprint analysis) - Any type of destructive or semi-destructive testing should be completed only after all non-destructive analyses are finished - Utilized the ACE-V method (analyze, compare, evaluate, verify) Slide 12: Handwriting Analysis: - Examines class characteristics first - Individual characteristics examined visually or microscopically - For example: - Singular difference: One singular difference doesn't mean there is a match Slide 13: Alteration, Obliteration, and Ink Differentiate - Evidence of a second writing instrument proves an alteration has been made - Visual examination - Microscopic examinations - Alternate light sources (and photography) -Ultraviolet (UV) and infrared (IR) light used for ink differentiate - Video spectral comparison (VSC) - Thin-layer chromatography (TLC) Slide 14: - Video spectral comparison (VSC) - Infrared imaging equipment: 'video spectral comparator' - Used for ink differentiation - Used to detect luminescent features such as holograms or watermarks (e.g. forgeries of passports or identification cards) - Think-layer chromatography (TLC) - Semi-destructive but definitive - Small punches(+3) of ink taken from minimally relevant line of writing using hypodermic needle - Ink separated from paper portion by introduction of solvent into a test tube - Ink and solvent solution subjected to chromatography **Week 12: Lecture 10B** Slide 1: Presence and Value of Evidence - Popular media portrays of crime scene investigation consistently show the timely recovery of key evidence - In reality: - Evidence may be minimal - Evidence present may not have evidentiary value - Owning (at least partially) to the CSI Effect Slide 2: Principles of Evidence Recovery - Evidence may only be collected after the crime scene has been documented in totality - Evidence collection as a skill - Combines knowledge of: -Criminal law -Rules of search and seizure -The value of evidence -Proper collection and analysis techniques - Only qualified crime scene investigators may collect evidence Slide 3: - Key principles of evidence recovery and collection: - \(1) Collection of evidence = loss of information - \(2) Potentially significant evidence may not be physically retrievable - \(3) Not all evidence at a crime scene has been intentionally deposited - \(4) Evidence may not be obvious -Spatial relationships Slide 4: Releasing the Crime Scene - Determination of when to release a crime scene generally responsibility of the officer in charge of an investigation - Criminal Investigator (detective) - Death Investigations: - Coroner or medical examiner has authority of the crime scene -Criminal Investigator must consult -Usually not released until autopsy process completed - Usually made in consultation with the crime scene investigator Slide 5: - Search warrant is required for re-entry - Integrity of evidence may be compromised - Crime scene investigator must be confident in decision to release the scene - Review processing plan generated in the initial walkthrough -"Is anything outstanding?" - Consult with specialized personnel called to assist Slide 6: - Additional protocol for the closing stages of crime scene investigation: - Cross-check evidence logs and written documentation against the packaged evidence inventory - Ensure everything properly bagged, labelled, and removed from the scene - Ensure all personal protective equipment (PPE) used is accounted for - Conduct equipment inventory -Ensure all equipment requiring decontamination are stored separately - Conduct equipment inventory -Ensure all equipment requiring decontamination are stored separately - Conduct final survey -Take a set of final photographs to show scene conditions upon release -Scenes could be held for multiple days: close scene at a certain. part of the day, keep scene security officer overnight -Could be opening and closing one scene many times, still do all proper procedure, still have to take photos at the end of the night before leaving a scene, and then take opening photos when reopened when entering the scene again - Document final conditions at the crime scene and authority of releases - Conduct final walkthrough Slide 7: - Processing of a crime scene is not as timely as portrayed in popular media - E.g. -Major crimes may be held for days or weeks - Rare cases, can be held for years - Case of serial killer Robert Pickton -Held for 2 years -125 Crime scene investigations 75,000 exhibits Slide 8: Cleaning the Crime Scene - Survivors, next of kin, or property owners left with the disarray of a processed crime scene - Presents challenges, potential for mental distress - Performed by specialized, privatized companies - Contracted - Employ individuals accustomed to medicolegal processes and death - Specialized cleaning services in variety of contexts -Usually not limited to only crime scene cleaning - Requires full PPE Slide 9: - Regulated by strict guidelines re: handling of contaminated, biological waste or other hazardous materials - Packaging in biohazard containers -Disposal by medical waste disposal companies - Duty to inform evidence discovered -Trained in the management of these scenarios -Guided by regulatory process despite Chain of custody being out of effect Slide 10: Submission of Evidence to the Forensic Laboratory - Maintain chain of custody - Evidence submission to forensic laboratory - Recall: -Centre receiving office (CRO) at the centre of forensic science -Civilian employees - Time frames dependent on: - Nature and complexity of required testing - Workload at the time of submission - Availability of particular forensic scientist - Oversight process in place -Involves forensic scientists reports to be reviewed by supervisor before approved for release Slide 11: Case File Preparation - Case file: Compliation of all case documents - Includes: - All documentation - Case narrative - All relevant logs - Chain of Custody forms - Laboratory requests and reports - Other relevant documentation Slide 12: - Case file forms basis for testimony in Court and substantiates validity of all evidence collected - Case narrative: - Running description of the entire crime scene -Presented in chronological order -What was done? What was discovered? What resources were required? - Objective account - Detailed yet concise - Does not include irrelevant information Slide 13: - Additional guidelines for generating a case file: - Report all information in chronological order - Report on facts: do not offer analyses or conclusions - First person, present tense - No slang or jargon - Refer to others in the investigation by role and/or name affiliation - Proofread - Ensure accurate cross-referencing -E.g. Between case narrative and photography log Week 13: Lecture 11A Slide 1: Review of Admissibility - Any relevant evidence should be admitted - Unless rule of law or policy requiring exclusion - Admissibility: process that governs which materials may be considered evidence - Reason a trial judge may deem evidence inadmissible: - Irrelevance - Prejudice - Unfairness - Unreliable Slide 2: - To be considered admissible, expert witness testimony must adhere to Daubert and Mohan - In the United States: - Frye v. United States (1923) -Frye Rule -Scientific methods/techniques must be generally accepted in their field - Daubert v. Merrell Dow Pharmaceuticals ß(1993) - Dismissed based on Frye Rule - Resulted in the Daubert guidelines -Introduced to clarify Frye Rule because methods or techniques did not have general acceptance in the field Slide 3: - Daubert guidelines: - Reliability -Based on reliable principles and methods, and tested by scientific method - General acceptance -Assessing degree of acceptance in scientific community - Known or potential error rates -consistently and reliably applied professional standards and known or potential error rates - Peer-review -technique subject to peer review Slide 4: - In Canada: R. v. Mohan (1994) - Mohan criteria: - Necessity in assisting trier of fact - Absence of an applicable exclusionary rule -Evidence must be given by a witness who has acquired special knowledge through study and experience (to differentiate expert witness vs. lay witness) -Evidence must not be obtained illegally -Qualified expert -Must have specialized knowledge or skill Slide 5: Legal System and the Court Players in a Criminal Trial - Judge - Trial by judge alone -Trier of fact - Trial by judge and jury -Charge the jury -Explain relevant rules of evidence -Explain standard of proof -Degree of certainty of a fact before the fact can be relied upon in support of a verdict - Jury - Trier of fact in trial by judge and jury Slide 6: - Lawyers - Crown (prosecution) and defense - Safety of society, the people - Objection -Formal, verbal declaration of belief that improper evidence adduced, or improper procedure employed -"sustained" (judge says "yes that objection is correct but rephrase") -"overruled" (judge says this, relates to whether objection is valid or not) - Witness -Give evidence or response to counsel -can be swearing on a religious text (can change depending on religion, affirm is a promise) Slide 7: Role of Crime Scene Investigator in a Criminal Trial - Lay witness: - heard, saw, done, experienced - factual testimony - Expert witness: may offer opinion on the work that was done and significance of the findings - Declared by judge - Crime scene investigators and forensic scientists as expert witnesses - Do not aim to assist prosecution in conviction - Unbiased advocate for the facts - Forensic scientist often called, they often conclude match if any - Misconception= CSI are to serve expert witness for prosecution Slide 8: Structure of a Criminal Trial - \(1) Introductions - Crown and defense counsel - Judge called "your honour" - \(2) Preliminary Matters - Pre-trial motions or amendments - \(3) Crown makes opening statement - Outlining Crown's case, highlighting legal issues of importance - Up to crown to show how criminal did do something - Idea of innocent until proven guilty - Think of outline as intro to essay - \(4) Defense counsel admissions - Accused may make an admission to certain facts so Crown is not required to prove them -Expedite the trial process -Fcous on the trial on what defense feels are key legal issues - Crown must agree, "agreed statement of facts" signed by both counsel parties -A document that agrees to dealing with other issues, and dismissing other charges Slide 9: - \(5) Crown calls evidence and witness takes the stand - \(i) Examination-in-chief -Party's questioning of its own witness -Defense counsel may be object on basis of: leading the witness, hearsay, relevance, opinions evidence -More selective than what is portrayed in popular media (interruption ruins focus, think amber heard vs. johnny depp trial) - \(ii) Cross-examination -Questioning of a witness by the opposing counsel - \(iii) Crown counsel re-examination -Party's questioning of its own witness following cross-examination -Serves to clarify; introduction of new material is not allowed (think about law and order case- sexual assault on sex worker, defense will use the word "rape", counsel can come back and clarify) - \(iv) Judge questions witness - \(v) Next witness called Slide 9: - Cross-examination - Questioning of witness by opposing counsel - Defense is not required to cross-examine -must determine whether it is necessary to examine a particular witness -May ask: -Does witness testimony damage our case? (less is more?) -Does witness testimony contradict our case theory? -Is it possible to elicit something favourable to the defense from this witness? Slide 10: - \(6) Crown closes its case - Must put all relevant evidence forth -Cannot withhold aspects of the case and introduce after defense has called evidence - \(7) Defense "motion of no evidence" - Known as a directed verdict acquittal in a jury trial - Is there sufficient evidence to permit a jury to reasonably convict? - \(8) Defense makes opening statement - Not mandatory - \(9) Defense calls evidence - \(10) Defense closes its case Slide 11: - \(11) Crown may call additional evidence - May seek to call further evidence in rebuttal or reopen its case -Limited to calling evidence in response to new facts by the defense -Reopening case only allowed in exceptional cases - \(12) Closing submissions - Both crown and defense - \(13) Judge makes a decision - May render a judgement immediately or may reserve judgement for a later date - \(14) Court deals with the accused - Sentencing may occur immediately or put to future date to allow counsel to prepare - If accused is not guilty, they are free to leave Slide 12: Testifying in Court - Crime scene investigator as an unbiased advocated for the acts - Defense counsel may attempt to discredit the expert witness or their actions - Review the case file in advance - Trial may occur after a significant amount of time has elapsed since processing - Importance of thorough documentation - Pretrial conference - Preparation of reports and demonstrative exhibits - Think to example of doctors using bid words and terms to communicate diagnoses, can't do that, must explain clearly Slide 13: How to be an Effective Expert Witness - Important guidelines for effective expert witness testimony: - Present in a professional demeanor -Dress professionally and appear sincere, objective, polite, and fair -Do not fidget, slump, or swivel - Make eye contact with the jury - Speak clearly -Avoid using filler words like "um" or "uh" - The importance of pauses -gives opposing counsel or judge the chance to object (gives a chance for them to object before you move onto another important point) - Avoid jargon -Speak with emphasis and educate using nontechnical language that a layperson can easily understand Slide 14: - Guidelines specific to cross-examination: - Witness does not need to answer with only a "yes" or "no" -Tactic to prevent explanation or contextual details; generally, not allowed as a blanket approach to testimony -May use leading questions in cross-examination -Right to explain rationale -Contrary to portrayals in popular media - Ask for clarification if required - Acceptance to say that you are not qualified to answer - Remain composed and polite -do not be defensive or snarky - May ask to respond to clarify your statements if you are not provided the opportunity initially -Be cautious: "have you ever made a mistake? Or "isn't it possible that..." **Week 13: Lecture 11A: Closing Remarks** Slide 1: Junk Science - **"**Science" that does not meet the fundamental requirements of science - But is presented to the public as scientifically verified - Can have no standardized methodology at all - Good science: - Defined methodolofy - Supported by other research (daubert and mohan criteria, peer review and general acceptance in the field) - Allows for independent testing and verification - Junk science: - Unproven or questionable -Ex. Trump saying "drinking bleach kills COVID" Slide 2: - National Academy of Sciences (NAS) released study called "Strengthening Forensic Science in the United States: A Path Forward" - Apart from nuclear DNA analysis: "No forensic method has been rigorously shown to have the capacity to consistently, and with a high degree of certainty, demonstrate a connection between evidence and a specific individual or source" - (National Academy of Sciences, 2009) - Report questioned the scientific basis for many forensic disciplines - Response: - Some disciplines defiant - Some worked towards development of objective comparison methods and known error rates - -We now know that specific matches needed to confirm fingerprint matches, need peer review Slide 3: - President's Council of Advisors on Science and Technology (PCAST) report: - "Without appropriate estimates of accuracy, an examiner's statement that two samples are similar -- or even distinguishable -- is scientifically meaningless. It has no probative value and considerable potential for prejudicial impact" - (PCAST, 2016) - Phrase "to a reasonable degree of certainty" no longer used - Suggests scientific certainty that many disciplines in forensic science do not have - Problematic when conclusions drawn using methods that have not been rigorously developed or independently verified - Miscarriages of justice - Wrongful convictions Slide 4: - Scientific methods under fire: - Fire investigations - Lead bullet analysis - Hair analysis (not referencing DNA) - Bitemark analysis - Not as reliable as been led to believe - Use and misrepresentation of these methods may be considered unethical - Inadmissible -(makes sense because they don't have error rates, not following Daubert, Mohan criteria) Slide 5: Fire Investigations - Analysis of fire-related incidents through fire dynamics - Knowledge through experience - No critical questioning, subjective - Shown to lead to incorrect conclusions - Response: - National Fire Protection Association (1992) introduced use of scientific method - Error rates are still largely unknown, used for context but not used for convictions - Innocence projects uncovered many convictions based on these methods Slide 6: Lead Bullet Analysis - Purported that bullets from same box of ammunition would be from same source and bullets from another box would have a different chemical makeup - National Academy of Sciences (2004) shows no scientific basis or support - Each box of bullets did not have a unique lead composition - By 2005, use of lead bullet analysis discredited and considered inadmissible and flawed - Lead to wrongful convictions, don't even use for contextual information Slide 7: Hair Analysis - Microscopic hair comparisons used to source hair to a single individual - Thickness - Pigment - Texture - Recent research and subsequent testing show results conflicting with those of DNA analysis - No longer used - Only way hair can be sourced to an individual is through DNA analysis Slide 8: Bitemark Analysis - Matching injury impressions of bitemarks on skin to dentition of a known suspect - Based on two assertions: -human dentition is unique -skin is a suitable medium (more problematic because skin is not a suitable medium for impressions as skin is plastic, flexible, can't hold bitemarks) -movement while being bitten can alter bitemark -looking for bitemarks themselves= junk science -dentition can be used for positive identification - No scientific validation or rates of accuracy - But used in many criminal prosecutions - Bitemark analysis as a subjective practice - Studies have shown higher rates of intra-observer error