History of Forensics and Key Figures

Forensic History and Careers: An Overview

• Forensic science applies scientific techniques to analyze criminal evidence, combining chemistry, medicine, biology, and pharmacology
• As a distinct discipline, forensic science emerged in the mid-19th century, propelled by death investigations
• Early forensic scientists were generalists, but modern experts specialize in areas like toxicology, psychology, and trace evidence analysis

Key Figures in Forensic Science

• Victor Balthazard (1850-1950): Parisian medical examiner who specialized in firearms and hair analysis
  • Balthazard pioneered photographic methods for examining firearm markings
  • Wrote the first book on forensic hair analysis
  • Determined the probability of unique fingerprints
• Alphonse Bertillon (1853-1914): Pioneered criminal identification using 11 body measurements and descriptions
  • The "Bertillonage" method was used worldwide, before fingerprinting became the standard
• Francis Galton (1822-1911): Developed a fingerprint identification system used by the British government
  • Authored "Finger Prints" in 1892, prioritizing fingerprinting in forensics
  • Classified fingerprints based on loops, arches, and whorls
• Calvin Goddard (1891-1955): A retired army physician who established scientific firearms analysis
  • Goddard worked with the Bureau of Forensic Ballistics and the FBI, creating modern firearm analysis tools
• Hans Gross (1847-1915): Magistrate who coined "criminalistics" for forensic evidence analysis
  • A generalist, he believed diverse fields contribute to evidence analysis
  • He published "Criminal Investigation" in 1893, an early forensic science textbook
• Edmond Locard (1877-1966): Criminologist trained in law and medicine, interested in trace evidence to link people and places
  • Locard's Exchange Principle posits that every contact leaves a trace
• Mathieu Orfila (1787-1853): Known as the father of forensic toxicology
  • Orfila studied poisons like arsenic and their presence in body fluids and tissues

The Influence of Fiction

• Sherlock Holmes stories shaped the public image of forensic science, explored diverse areas, and inspired pioneers

Science and Law in Modern Forensics

• Forensic evidence helps judges and juries reach verdicts
• Scientific Method: Hypothesis formulation, testing, revision, and repetition until data agreement
• Forensic science distinguishes evidence from coincidence, rejects nonsensical hypotheses, draws general conclusions, and tests hypotheses in parts
• Scientists form justified conclusions, but acknowledge the unknowns through "contrite fallibilism"
• The legal system is adversarial, unlike the scientific method

Contemporary Forensic Practice

• Forensic scientists work in public or private labs
  • Full-service labs handle DNA, hair analysis, firearms, trace evidence, and fingerprinting
• Modern labs must be accredited, with certified scientists passing exams

Legal Proceedings and Evidence

• Civil cases involve disputes between individuals
• Criminal cases involve government charges
• The prosecution/plaintiff files charges; the defendant Forensic scientists can testify for either side
• Jurisdiction is the region where law enforcement has authority
• Judges/juries ("trier of fact") decide based on evidence presented
• Grand juries determine if enough evidence exists to charge a crime
• Misdemeanors are minor offenses; felonies are serious offenses
• Subpoenas compel witness testimony
• Voir dire involves scientists proving their qualifications
• Direct examination uses direct questions, but defense can cross-examine

Forensic Ethics and Rules of Evidence

• Professionals provide complete, honest reports and testify ethically, despite the absence of a single ethics code
• "Prosecutorial bias" occurs when scientists seek results favoring their side
• Evidence must be court-approved and relevant to a defendant's fate, passing through admissibility rules

Evidence Admissibility and Standards

• Admissibility proceedings introduce scientific methods in forensics, filtering out pseudoscience and relying on reliable technology
• Frye Standard: requires general acceptance in the relevant scientific field
  • Difficult to apply as science advances
• Federal Rules of Evidence (1996): Allow qualified experts to testify, aiding jury comprehension without proving qualifications
• Daubert Standard: Trial judge determines evidence relevance/validity, ensuring scientific methods are valid
  • The "Joiner case" mandated passing both Daubert and relevance tests
  • "Kumho Tire" extended this ruling to experts in any field

Evidence Categories and Crime Scenes

• Inculpatory evidence establishes guilt, while exculpatory evidence exonerates the defendant
• Direct evidence establishes a fact (eyewitness), circumstantial evidence requires inference
• Reconstruction provides a crime timeline
• Associative evidence reconstructs a crime scene
• Class-characteristic evidence doesn't identify a suspect, individual evidence does
• Exclusionary and incriminating evidence are both important
• Biological, chemical, trace, and questioned document evidence are all important types
• Can also include fingerprints, impressions and firearms

Crime Scene Investigation: An Overview

• Crime scenes vary by location, size, type of crime and condition
• Processing a crime scene involves preserving, collecting, and recognizing all physical evidence
• Evidence testing provides investigative leads, suggests MO, tests witness statements, identifies suspects/substances, and links people

Crime Scene Investigation: Team and Documentation

• Forensic investigations depend on resources
• Crime scene teams include technicians, major crime squads, traditional units, lab scientists, and collaborative efforts
• First responders stabilize victims, search for suspects, detain witnesses, and secure the scene
• Initial investigators note entry/exit points, conditional evidence, and weather, and notify personnel
• Crime scenes are documented through writing, photos, videos, and sketches
• Photos provide accurate records but can be manipulated
• Notes describe the scene and activity with the 5 W's
• Video recordings are standard without audio and people
• Sketches use triangulation, baselines, and polar coordinates to obtain measurements

Crime Scene: Searches, Evidence and Reconstruction

• Initial search locates obvious items, documented through systematic search patterns
  • Including link, zone, spiral, and linear methods
• Important items are marked and moved items are documented for separate analysis
• Evidence collectors must document evidence with packs and marks immediately
  • Primary and secondary containers are used, with paper sheets for trace evidence
  • Volatile items are sealed airtight, while biological items are air-dried
• Reconstruction determines crime events through physical evidence analysis, following a scientific method

Death Investigation: An Overview

• Experts investigate unexpected deaths involving poison or injury
• Determining the cause of death identifies public health issues, inheritance matters, etc
• Coroners conduct such investigations in English-speaking countries
  • Standards for training were only established in the 19th century
• Forensic pathology arose as a specialty in the 19th century
  • Death investigations determine cause/manner and present physical evidence to support conclusions

Cause, Manner, and Time of Death

• Cause of death is the initiating disease or injury
• The mechanism of death is the abnormality preventing life
• The manner of death includes natural causes, homicide, suicide, accident, and undetermined cases
• Post-mortem interval (time of death) is investigated through three major body changes
  • Livor mortis causes discoloration that appears within minutes but disappears after 36 hours
  • Algor mortis is the cooling of the body
  • Rigor mortis is the stiffening of muscles that occurs ~4 hours after death and disappears after 24-36 hours

Tools, Autopsy, and Trauma

• Investigative tools include medical history reviews, witness statements, and scene examination
• Religious or family objections are respected when it comes to autopsies
• Autopsies involve organ removal through incisions, including inframammary and brain examinations
• Documentation is important, with autopsy photos and samples preserved in formaldehyde
• Aortal blood and urine are tested for drug presence
• Traumatic deaths are classified as mechanical, thermal, chemical, or electrical

Mechanical, Thermal, Chemical, and Electrical Deaths

• Mechanical deaths: Sharp force causes incised wounds
  • Blunt force causes laceration, and firearms cause penetrating or perforating wounds
  • Reaction of CO from bullet with blood, blackening of skin, laceration severity can determine distance
  • Motor vehicle collisions mainly cause bleeding and lung leaking
  • Injuries such as beatings, contusions are hematomas are possible
• Chemical trauma: Includes depressant overdoses (e.g., opiates, alcohol) and stimulant overdoses (e.g., cocaine)
  • CO gas causes death
• Thermal: Hypo/hyperthermia disrupts homeostasis
  • Fire deaths happen primarily from smoke inhalation
• Electrical: Shocks can cause ventricular fibrillation (low voltage) or tetany (high voltage)
  • Electricity damages tissue through poration
• Asphyxia results from oxygen deprivation caused by any of the above methods

Forensic Toxicology and Pharmacology

• Forensic toxicology studies poisons in legal cases, performed by toxicologists or drug analysts
  • ADME: absorption, distribution, metabolism, excretion
    • These are tracked with blood, urine, or stomach contents in postmortem settings

Common Classes of Drugs and Poisons

• Amphetamines are stimulants that elevate heart rate, blood pressure, and breathing
• Cocaine is a similar stimulant metabolized into methylecgonine
• Cannabinoids affect mood, perception, and behavior, measured via blood/urine
• Pharmaceutical overdoses, accidental or suicidal, are referred to as polypharmacy
• Non-medicinal agents include alcohols, cyanide, carbon monoxide and hydrocarbons
  • Alcohols disrupt cell signaling and are tested via gas chromatography
  • Cyanide interrupts the electron transport chain
  • CO gas disrupts hemoglobin's oxygen transport

Drug Testing Techniques

• Two-step drug testing includes presumptive and confirmatory tests in blood and urine
• Immunoassays measure substances with antibodies
• Chromatography separates chemicals through thin-layer methods
  • Separating chemicals with a mobile phase
• Confirmatory gas chromatography separates compounds by interaction with biological tissues
  • A sample is vaporized and sent through column of carrier gas
• GC is paired with mass spectrometry, Molecules here are ionized and recorded as virtual fingerprints
• Liquids GC-MS is the same but liquid is used instead of gas
  • LC is often combined with MS series, and its called tandem mass spectrometry

Metal Analysis, Pharmacokinetics, and Drug Testing

• Metal analysis occurs through colorimetric testing
• Inductively coupled plasma-mass spectrometry is used to ionize specimens and measure mass and charge
• Pharmacokinetics studies how drugs/toxins move
• Toxicogenomics examines genetic impacts
• Workplace drug testing implements cut-off limits, and post-mortem testing is more challenging

Legal Framework for Controlled Substances

• The Controlled Substances Act regulates controlled substances and categorizes them by abuse potential
  • Schedule 1 drugs have high abuse potential and no medical use (e.g., heroin, LSD)
  • Schedule 2 drugs are addictive but have medical uses (e.g., meth, morphine)
  • Schedules 3 and 4 have decreasing abuse potential and valid medical uses
• Criminal prosecution requires identifying the substance and determining its amount
• SWGDRUG recommends analysis/testing
• Analysis is divided into botanical and chemical examinations

Identification of Specific Drugs

• Marijuana detection involves identifying the plant (cystolithic hair pattern) and detecting plant resin
• Hashish is identified similarly to marijuana
• Peyote is physically identified by its button shape and citrus segments and white fluff, containing mescaline
• Mushrooms require more testing with psychoactive components (psilocin and psilocybin)

Drug Testing: Chemical Examinations to DNA and the Pitchfork Case

• Chemical examinations use wet chemical or instrumental techniques
• Microcrystal tests dissolve substances to form unique crystals for comparison
• Extractions separate substances through physical or chemical methods
• Infrared spectroscopy identifies substances by their infrared light absorption patterns
• Clandestine drug labs can be small or large, remote or urban, with trained chemists on staff

DNA Analysis - Techniques and History

• DNA typing revolutionized forensic science with individual identification techniques
  • The process involves a double-stranded molecule in cell nucleus, and double-helix carries genetic code
• Nucleotides are composed of sugar, phosphate, and bases (A, G, C, T)
• Watson, Crick, and Franklin proposed the double helix structure
• DNA carries inherited characteristics through 23 chromosome pairs (XX for female, XY for male)
• In the Colin Pitchfork case, DNA profiling was used to catch a criminal
  • Sir Alec Jeffreys took blood samples and caught two murderers

DNA Testing and STR Analysis

• Early DNA testing required a lot of test
• It was introduced to the US in 1986
• Known as CODIS
• 3% of DNA codes for proteins, and repetitive regions are satellite DNA
  • Including microsatellites/short tandem repeats (STR) and minisatellites/variable number tandem repeats (VNTR)
• Microsatellites are 2-7 bps that long
• The repeats do vary
• Heterozygosity is a gene consisting of two different alleles. Homozygosity means of just one
• analyst estimates repeat length and identify a person
• RFLP is more outdated and STR is the modern approach
• DNA is isolated from cells that contain bones and semen
• Degradation occurs from many bps, nuclease and enzymes

DNA Amplification to STR Analysis

• DNA is amplified through PCR in three steps
  • Denaturation to separate strands
  • Primer attachment
  • Extension with taq polymerase
• Creates two copies of DNA
• 20-30 rounds exponentially amplify copies
• Current standard is STR due to core 13 loci for CODIs
• Capillary electrophoresis is used
• DNA has fluorescence
• It is separated and code color signals are given
• analysts interpret alleles
• STR creates 15 phenotypes
• Single locus cannot create individual blood of blood
• Mitochondrial DNA (mtDNA) maternally inherited, is quick to mutate
• Y chromosome STR is unique to males

Forensic Psychology: History and Application

• Forensic psychology, linking psychiatry to legal cases, has gained recognition since the 1970s
• Before that, it did not factor in criminal cases. 1962 allowed testimony from experts
• Personality determines conduct in crime scene. Assesses psyche by quasi-qualitative metrics

Psychological Testing Methods

• Projective tests - Individuals respond to ambiguous stimuli and reveal aspects
• Rorschach Inkblot Test is common tool, and helps assess the dynamics of personality, helps identify if mental illness is present
• TAT subjects write story that assess subject views pictures and scenarios
• Personality Inventories, which assess individuals via standard assessment.
• Intellectual tests are specialized for legal and cognitive tests
• Clinical interviews inform and assess the patient

Deceptive Behavior and Applications

• Malingering is conscious behaviour and an attempt to fake being sick
• Dissimulation minimizes symptoms
• To prove this is rationalize with behavior that seems irrational
• Competency is used to asses the validity
• Competency states that the statements are true, and the defendant comprehends/ and can follow all directions

Legal Insanity, diminished capacity and sentencing

• Definition of insanity lies with the McNaughter rules and the Modern Penal Code in law
• Also depends on cognitive components
• Diminished capacity is lower homicide rates where one commits unknowing and without bad intention or foresight for the act
• Those that commit the acts are psychiatrists, or behavioral scientists that advise sentence

crime scene science

• Helps understand crime/intent
• offender has traces
• The homicides are split in two types of actions planned or unorganized
• Deviant actions

crime scene MO and offender

• MO is what they believe during the act
• Criminal profiles are demographic in the 1970
• Identify the victim
• What happened during the crime
• The MO comes from the mind
• Inconsistent with the crime and victim
• The bodies location is how they relate and plan and prepare

Bloodstains and Biological Stains : Identification

• Involve knowing the crime
• Use geometrical
• Modern began in 1800
• Since 1955 it is forensics
• extra fluid
• Plasma - serum
• Nuclea
• To splatter surface force

Death examination: Blood

• The geometry of stain help determine the way that blood is going
• Draw a line to view
• This give 3D shapes with angle

Bloodstain patterns, Castoff patterns and stains

• Affects by amount of pressure surface type
• The pattern determines which way
• The location or type of object can tie
• Gunshots may mist
• From wound they give splatters 1-3mm
• The area can be similar
• Multiple can be drop of the pattern
• Volume freshness type location all affect the surface and patter

pattern alterations

• Gravity releases for splatter
• High speed is gravity is gravity will happen
• Trauma can be removed too
• Similar can be distinguished - the arterial spray be removed for viewing

Alter stains

• Can change with time and weather
• All has to see what exactly is going to change/ is not to make correct results

The stains : clothing

• Has to view where
• How the stains
• Document to not misremember on something

The Absence and Identification of Blood

• The blood is altered
• They remove is to view
• Bodily fluids in serology is used
• Screening test with help
• Has some problems

Chemical Blood Test

False information can be mixed

• Blood testing with benzidine and hemastix
• Lumio will show cleaned blood
• It acts with antibody
• Can show enzymes

Body fluids

seminal acids

• The test helps identify sperm.
• SAP part in class
• And the colour changes will show

Fluids - saliva

• It acts from acids from salt
• Iodide is for starches and the store is produced
• Not because some are creatine
• Has secretions that test SA
• Destroys the testing needs