Forensics Midterm Study Guide PDF

· Testimonial evidence spoken statements : , (ie. eyewitness) · Physical evidence tangible : evidence that can...

· Testimonial evidence spoken statements : , (ie. eyewitness) · Physical evidence tangible : evidence that can connect an individual to the scene of a crime. · Document evidence : documents containing information that can link an individual to a crime scene. · Sir Francis Galton : Developed the first classification of fingerprints (ie Loop whol. , , archs Hans Gross: Scientific fields - investigations · · Alphonse Bertillon: Biometrics as identification · Edmund Locard Developed : the principle of exchange. ~ Mathieu Orfila Forensic Toxicology · : Leone Lattes Blood can be grouped (blood type · : · Calvin Goddard : Developed identification process for firearms and projectiles. · Crime Scene specialist An individualwho : views and documents crime scenes as well as evidence. Mr (i e.. friction ridge toxicology etc. , , · Lab specialist : An individual who tests evidence from a crime scene for various forms of scientific evidence such as. DNA , blood, Drugs etc Contamination Other materials : come into contact with a piece of evidence , leading to the evidence being altered. · Chain of Continuity/Custody A : record of every point of contact that each piece of evidence has come into ~ · Locard's principle of exchange : All objects that come into contact with each other leave behind evidence of said contact. Deduction reasoning general ideas to down specific possibilities · : narrow  · Inductive reasoning : Specific ideas -> general explanations Different Types of Physical Evidence : · Drugs : any mind altering substance including alcohol and cannibis. · Explosives any object with explosive properties (ie detonator etc. :. , · Documents : Documents can include information linking a suspect to a crime. · Blood , semen , saliva: Substances containing DNA that can build a DNA profile on a suspect. · Glass Fragments : can be studied to determine order of shots in cases involving projectiles. ~ · Hair : Human and/or pet hair can be used to link a suspect to crime scene. I · Fingerprints Fingerprints left at : a crime scene can be used to identify a suspect. · Firearms & Ammunition Firearms and ammunition can : be recovered and identified to link an individual to a crime scene. I · Impressions : Tire/foot impressions can be used to identifyvehicles/individuals. · Organs & Physiological Fluids : Physiological fluids can be tested to identify drugs/poison in a. person's body · Paint : Paint chips/marks can be used to link objects such as vehicles to a crime. (ie. it and runs) V · Petroleum Products : Residue from products such as gasoline can help to conclude the nature of a crime such as. arson Plastic Bags Plastic bags found at. · : a crime scene can be compared to bags found in a suspects possesion  · Plastic/Rubber/ Other Polymers : can link a victim to a crime · Powder Residue If powder residue : is found at a scene it can help to conclude if firearms were used. I · Serial Numbers: Serial numbers can be used to link individuals in possession of certain items , to a crime. I · Soil & Minerals : Soil and minerals can be tested to link a suspect to a location. · Toolmarks Tool mark evidence : can help investigators determine what tools were used at the scene of a crime ~ · Vehicle Lights : Vehicle lights can be examined to determine if a vehicle was onloff during a crime, broken vehicle lights can be examined/ compared to pieces found at a scene. · Wood & Other Vegetative Matter : Can be used to connect a suspect to the location of a crime. - · Innocent mechanism Us. evidentiary value : Innocent mechanism can be explained by Coincidence. Evidentiary value is something that is otherwise unexplainable. · Expert witnesses : An expert witness is an individual that is called upon to make a statement in court based on their superior knowledge in a specific - area. Cognitive bias : A bias that created through an individuals · is own conclusions. · Confirmation Bias : A bias that is created due to what an individual believes to be true. ~ · Contextual Bias: A bias that is created by the context of a situation. ~ · Dr. Charles Smith: Performed autopsy but went under investigation and was found to have manyresults that were incorrect due to malpractice. ~ · The public prosecutions service of Canada : The standard that is followed by those who work in crime , along with training. · IA) : International Association of Identification SWGFAST : Scientific Working Ridge Analysis study & Technology · Group on Friction the they had already been convicted CSI Effect After the show CSI out, there noticeable uprise in members of cclaiming that individuals were innocent even after. : came was a that lacked forensic evidence. it was also found that jurors were less likely to convict in cases  · SWGTREAD : Scientific Working Group of Tire Tread and Footwear Impression Evidence ~ · Biology Services : The department that is in charge of the testing and identifying of biological materials / Firearm and tool · mark identification : The department that is in charge of the testing and identification of firearms and tools. I ~ · National Anti-Counterfeiting Bureau (NACB) : The bureau that is responsible for the supervision of all bank activity in Canada as well as the supervision of counterfeit money. · Toxicology Services: The department that is responsible for the testing of biological evidence for traces of drugs , alcohol and , poison. ~ · Trace Evidence Evidence that : is non-biological · Type of equipment needed for proper evidence handling plastic bags gloves paper bays clamshells , tin : , , , cans , swabs distilled water , , gunshot residue kits Fingerprints Structure of friction ridges : What does fingerprint secrete?: Amino acids sebaceous oils , sweat , fatty lipids organic & inorganic materials · a , , Fingerprint · forms: arch , loop, whorl Major ridge path deviations : Bifurcation Island ridge ending etc. · , , , * go over the example image · Fingerprint matrix : The substances that are deposited/removed when an impression is made · Development mediums Tools which : are used to develop a fingerprint for investigation · Cyanoacrylate (CA) (AKA superglue) Can be used to create a sample of : a fingerprint, will also preserve DNA , risk of overfill ; rendering sample unviable. · Rhodamine-G-G (RGG) , Adrox and Basic yellow : , Green FLS · Basic yellow/red : Blue FLS  · Forensic light source (FLS) A forensic light : source can be used to create more contrast in a fingerprint sample. V · Paper or porous substrates: Some surfaces may absorb amino acids and other secreations. 1 , 8 Diafluorin-a-one : used to chemically ninhydrin · : amino acids absorbed substrates. by pourous · 1 ,2 Indanedione Zinc Chloride : · Blood reagents Blood reagents can : be used to test if the fingerprint in question has any blood and if that blood , is animal or human. Footwear/Tiretreadfootweatire treadpreservationStabilizingagentscan -used be to preserve footprints and fire treads Dental cement. can be used to make molds of footprinta Class characteristics : · Characteristics that one or more samples has in common. Not enough to create a positive identification. Accidental Crandomly acquired) characteristics Characteristics that : are acquired through individual arcumstances. · Degree of wear: The degree to which a footwear outsole or fire has been damaged. · Insufficient detail : When a sample is lacking enough individual detail to generate positive match a. · Impression : An indentation or "print" made by footwear or firetread · known footwear or tire A sample used to compare to footwear : or fire impressions found at. a scene Mold characteristic : Design and size features of mold · a · Physical size : The measurements of a footwear or fire. · Position and orientation of wear: The way that a footwear outsole or fire is worn.. (i e outer part of an outsole outer part of.. , a tile · Tears A rip : found in footwear or fire that a is not a design characteristic.  · Test impression : An impression that is created in order to compare to an impression that was obtained at a. scene · Three-dimensional impression : An impression with measurements of length width and , , depth · Transfer impression A footwear/tire impression made : on a 2-D surface when footwear/tire picks up dust , residue, mud, blood etc. , · Two-dimensional impression : An impression with measurements of length and width Wear : The · "damage" done to an object after continued. use · The standard 7 conclusions for both footwear and fire tread : 1) Lacks sufficient detail 2) Exclusion 3) Indication of non-association 4) Limited association of class characteristics 5) Association of class characteristics 6) High degree of association 7) Identification · Overview of Colonel Russell Williams case : Footwear and Tire impressions led to his conviction Bloodstain SWESTAIN : Scientific Working Group on Bloodstain Patter Analysis- Passive produced from free falling or projected droplets · stains : · Drip pattern The : result when blood is dripped into another liquid · Drip stain:The stain that is created when blood drops due to gravity · Drip trail A : trail of blood that is created when a subject moves/is moved while bleeding. · Expiration pattern A pattern that is created : due to blood that has been project out of mouth/nose/wound due to air flow. · Aspiration Air bubbles : in the blood · flow pattern When an area of blood moves/settles due to gravity : · Pool An : area of blood that has been collecting in one spot  Projected pattern The by a projective · : pattern that is left byblood that has been forced out Satellite stain : A stain that · is created from a parent stain · Serum stain : The stain that is left by blood that has been separated into it's different elements due to coagulation · Parent stain : the origin of a satellite stain · Transfer stains : ↓ · Cast-off pattern A : blood pattern that arches. · Insect stain : A stain that is created due to insect activity Swipe pattern Transfer of blood from surface to another · : one · Wipe pattern When an object has run through : a wet blood stain · Impact stains The stain that : is created when blood exists the body due to impact. · Back spatter pattern : When blood exits the body in the opposite direction of the impact. Forward spatter pattern: When blood exits · the body in the same direction as the impact Mist pattern : When the force at which blood exists the body strong that tiny droplets create the stain. · is so Misc. Terminology · : ↓ · Blood clot A gelatinous mass of : blood · Bubble ring : A ring inside of a blood stain caused by air in theblood.  · Directionality The direction at which blood travels when : it exist the body · Edge characteristic: Characteristics around the perimeter of a blood stain. Perimeter stain Altered stain with the same perimeter as characteristics as the original stain · : · Void A "plank space" within : a blood stain y Anatomy of blood : Blood used to provide the body with nutrients well rid the body of waste · is as as · Blood Blood : is made up of red blood cells (erythrocytes), white blood cells (leukocytes) and plasma ,. · General features of bloodstain formation The : type of pattern produced is dependent on force and other external factors. · Information needed for bloodstain patter interpretation : 1) Direction of origin 2) Angle which droplets struck a surface 3) Position of victim 4) Movement of victim 5) Minimum number of blows 6) Location of perpitrator · The mathematical equation to determine the angle of impact sinA-width of bloodstain : where-angle length of bloodstain · Bloodstain pattern and velocity : when force increases , velocity increases · lower force bigger droplets higher force : smaller droplets · Area of convergence The direction of splatter can be retraced : to determine the location of splatter-producing event · Area of origin: The position/location at which the blood exited the body - String method When string is connected to each of the blood spots and connected to an at the angle of impact. the point at which the strings connect is the of origin. · : a axis area · Grid method When : a grid is placed over the blood stain · Perimeter ruler method When rulers : are placed on the perimeter of a blood stain