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Introduction to Forensic Science


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Title: Introduction to Forensic Science

Introduction to Forensic Science to the Law
  • Chapter 1

Forensic Science
  • It is the study and application of science to
    matters of law (criminal and civil)
  • Includes the business of providing timely,
    accurate, and thorough information to all levels
    of decision makers in our criminal justice system
  • Also called criminalistics

Criminalists vs Criminologists
  • A criminalist examines physical evidence for
    legal purposes
  • Criminologists study the crime scene for motive,
    traits, and behavior as to help interpret the
  • They learn to think like criminals

Forensic Scientists
  • Applies the principles and techniques of the
    physical and natural sciences to the analysis of
    the many types of evidence that may be recovered
    during a criminal investigation
  • May also provide expert court testimony
  • Known as an expert witness
  • Individual whom the court determines possesses
    knowledge relevant to the trial

The Crime Lab
  • Characterized by rapid growth due to
  • Supreme Court decisions in the 1960s placing
    greater emphasis on scientifically evaluated
  • Accelerated drug abuse
  • Initiation of DNA profiling
  • 350 public crime labs exist at federal, state,
    county, and municipal levels

Crime Lab Services
  • 5 exist
  • Physical science
  • Chemistry
  • Physics
  • Geology
  • Biology
  • Firearms
  • Document
  • Photographic

Physical Science Unit
  • Incorporates the principles of chemistry,
    physics, and geology to identify and compare
    physical evidence

Biology Unit
  • Applies the knowledge of biological sciences in
    order to investigate blood samples, body fluids,
    hair, and fiber samples

Firearms Unit
  • Investigates discharged bullets, cartridge cases,
    shotgun shells, and ammunition

Document Unit
  • Provides the skills needed for handwriting
    analysis and other questioned document issues

Photographic Unit
  • Applies specialized photographic techniques for
    recording and examining physical evidence

Other Crime Lab Services
  • Toxicology Unit- examines body fluids and organs
    for the presence of drugs and poisons
  • Latent Fingerprint Unit- processes and examines
    evidence for latent fingerprints
  • Polygraph Unit- conducts polygraph or lie
    detector tests
  • Voiceprint Analysis Unit- attempts to tie a
    recorded voice to a particular suspect
  • Evidence Collection Unit- dispatches specially
    trained personnel to the crime scene to collect
    and preserve physical evidence

Other Forensic Science Services
  • Forensic Pathology- concentrate closely on the
    understanding of types and causation of injuries
    and causes of sudden and unnatural death
  • Deals with the different stages of death
  • Rigor mortis- stiffening of the body (occurs
    within first 24 hours)
  • Livor mortis- settling of blood closest to the
    ground (occurs up to 12 hours)
  • Algor mortis- results in loss of heat

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Other Forensic Science Services
  • Forensic Anthropology-concentrates on the
    identification of deceased individuals whose
    remains are decomposed, burned, mutilated or
    otherwise unrecognizable
  • Forensic Entomology- is the study of insects and
    their relation to a criminal investigation,
    commonly used to establish the time of death
  • Forensic Psychiatry- work with courts in
    evaluating an individual's competency to stand
    trial, defenses based on mental diseases or
    defects (e.g., the "insanity" defense), and
    sentencing recommendations

Other Forensic Science Services
  • Forensic Odontology- evaluates teeth to determine
    the identification of the deceased
  • Forensic Engineering- investigation of materials,
    products, structures or components that fail or
    do not operate/function as intended, causing
    personal injury for example
  • Cybertechnology- involves the examination of
    digital evidence

Major Crime Labs
  • FBI- Federal Bureau of Investigations
  • DEA- Drug Enforcement Agency
  • ATF- Bureau of Alcohol, Tobacco, Firearms, and
  • US Postal Service
  • US Fish and Wildlife Service

The Crime Lab
  • History
  • First established in 1910 by Locard
  • First police crime lab established in 1923 in Los
    Angeles, CA
  • Scientific Crime Detection Lab established in
  • First FBI crime lab opened in 1932

Developments in Forensic Science
  • 700s AD- Chinese used fingerprints to establish
    identity of documents and clay sculptures
  • 1000- Roman courts determined that bloody palm
    prints were used to frame a man in his brothers
  • 1149- King Richard of England introduced the idea
    of the coroner to investigate questionable death
  • 1200s- A murder in China is solved when flies
    were attracted to invisible blood residue on a
    sword of a man in the community
  • 1598- Fidelus was first to practice forensic
    medicine in Italy

Developments in Forensic Science
  • 1670- Anton van Leeuwenhoek constructed the first
    high powered microscope
  • 1776- Paul Revere identified the body of General
    Joseph Warren based on the false teeth he had
    made for him
  • 1784- John Toms convicted of murder on basis of
    torn edge of wad of paper in pistol matching a
    piece of paper in his pocket
  • 1859- Gustav Kirchoff and Robert Bunsen developed
    the science of spectroscopy
  • 1864- Crime scene photography developed

Developments in Forensic Science
  • 1879- Alphonse Bertillion developed a system to
    identify people using particular body
  • 1896- Edward Henry developed the first
    classification system for fingerprint
  • 1900- Karl Landsteiner identified human blood
  • 1904- Edmond Locard formulated his famous
    principle, Every contact leaves a trace
  • 1922- Francis Aston developed the mass

Developments in Forensic Science
  • 1959- James Watson and Francis Crick discover the
    DNA double helix
  • 1977- AFIS developed by FBI, fully automated in
  • 1984- Jeffreys developed and used the first DNA
    tests to be applied to a criminal case

People of Historical Significance
  • Albert Osborn- developed the fundamental
    principles of document examination
  • Walter McCrone- utilized microscopy to examine
  • Hans Gross- wrote treatise on criminal
  • Edmond Locard- considered the father of
    criminalistics responsible for Locards exchange
  • States that when a criminal comes in contact with
    an object or a person, a cross transfer of
    evidence occurs

People of Historical Significance
  • Mathieu Orfila- father of forensic toxicology
  • Alphonse Bertillion- devised first scientific
    system of personal identification
  • Francis Galton- conducted first definitive study
    of fingerprints and their classification
  • Leone Lattes- developed a procedure to determine
    blood type from dried bloodstains
  • Calvin Goddard- used a comparison microscope to
    determine if a particular gun fired a bullet

The Crime Scene Team
  • A group of professional investigators, each
    trained in a variety of special disciplines
  • Team members include
  • First police officer on the scene
  • Medics (if necessary)
  • Investigator(s)
  • Medical examiner
  • Photographer and/or Field Evidence Technician
  • Lab Experts

  • pathologist serologist
  • DNA expert toxicologist
  • forensic odontologist forensic anthropologist
  • forensic psychologist forensic entomologist
  • firearm examiner bomb and arson expert
  • document and handwriting experts
  • fingerprint expert

Laws that Pertain to the US Criminal Justice
  • The US Constitution
  • Statutory Law
  • Common Law or Case Law
  • Civil Law
  • Criminal Law
  • Equity Law
  • Administrative Law

US Constitution
  • Supreme body of laws that governs our country
  • Overrules the constitutions of individual states

Statutory Laws
  • Are written laws as enacted by a government body
    such as Congress
  • Are based on the Constitution

Common Law
  • Also known as case law
  • Are made by judges
  • Makes for predictability and consistency in how
    the law is applied

Civil Law
  • Also known as private law
  • Deals with relationships between individuals
    involving properties or contracts
  • Regulates noncriminal relationships between
    individuals, businesses, agency of government,
    and other organizations
  • Includes contracts, marriages, divorces, wills,
    property transfers, negligence, and products
    manufactured with hidden hazards
  • More concerned with assigning blame than intent

Criminal Law
  • Also known as public law
  • Deals with regulation and enforcement of rights
  • Concerned with offenses against an individual
    that are deemed offensive to society
  • Cases tried are always the person vs the state
  • Those laws that are broken fall into 1 of 2 main
  • Misdemeanor- is a minor crime such as theft,
    minor assault and battery, or possession of small
    amounts of illegal drugs
  • Felony- is a major crime such as murder, rape,
    armed robbery, serious assaults, dealing in
    illegal drugs, fraud, auto theft, or forgery

Equity Law
  • Remedial or preventive law
  • Are for cases not covered by common law
  • Restraining orders
  • Injunctions

Administrative Law
  • Laws established by governmental agencies such as
    the IRS, Social Security Administration, or the

The Bill of Rights
  • The right to be presumed innocent until proven
  • The right not to be searched unreasonably, either
    on ones person or in ones home
  • The right not to be arrested without probable
  • The right against unreasonable seizure of
    personal property
  • The right against self-incrimination
  • The right to fair questioning by police

The Bill of Rights
  • The right to protection from physical harm
    throughout the justice process
  • The right to an attorney
  • The right to trial by jury
  • The right to know any charges against oneself
  • The right to cross examine prosecution witnesses
  • The right to speak and present witnesses

The Bill of Rights
  • The right not to be tried again for the same
  • The right against cruel and unusual punishment
  • The right to due process
  • The right to a speedy trial
  • The right against excessive bail
  • The right against excessive fines
  • The right to be treated the same as others,
    regardless of race, gender, religious preference,
    country of origin, and other personal attributes

Steps in Pursuing Justice
  • If a crime is committed these are the steps to
    take while pursuing justice
  • Police investigate what happened
  • Information is collected
  • Crime scene is documented and searched for
  • All info is assembled into a report and sent to
  • Investigation continues until probable cause is
  • An arrest warrant is issued for the suspect
  • The suspect is arrested
  • Individual is booked, fingerprinted, photographed
    and informed about his/her rights

The Miranda Rights
  • Miranda v. Arizona (1966)
  • Before a law enforcement officer may question a
    suspect regarding the possible commission of a
    crime, he or she must inform the detainee about
    his or her Miranda rights, making sure the
    detainee understands them

The Miranda Rights
  • Warning of Rights
  • You have the right to remain silent and refuse to
    answer questions
  • Anything you do or say may be used against you in
    the court of law
  • You have the right to consult an attorney before
    speaking to the police and to have your attorney
    present during questioning now or in the future
  • If you cannot afford an attorney, one will be
    appointed for you before any questioning if you
  • If you decide to answer questions now without an
    attorney present, you will still have the right
    to stop answering at any time until you talk to
    an attorney
  • Knowing and understanding your rights as I have
    explained them to you, are you willing to answer
    my questions without an attorney present?

Steps in Pursuing Justice
  • Person is brought before a magistrate judge who
    informs the individual of the charges, his/her
    rights, and bail
  • The person may also enter a plea of guilty, not
    guilty, not guilty by reason of insanity, double
    jeopardy (been tried for same crime in same
    court), or nolo contendere (no contest)
  • If a plea of guilty is entered, the person is
    brought before a preliminary or evidentary
    hearing (no jury present)
  • Most states use a grand jury
  • Will determine if there is enough evidence to
    bring the accused to a formal trial
  • The prosecutor presents evidence and the grand
    jury (16-23 citizens) decide the fate of the
  • If the grand jury decides there is enough
    evidence, a trial date will be set

Steps in Pursuing Justice
  • If a plea of not guilty by reason of insanity is
    entered, the defendant will have to prove, by
    clear and convincing evidence, that at the
    time of the commission of the acts constituting
    the offense, the defendant, as a result of a
    severe mental disease or defect, was unable to
    appreciate the nature and quality or wrongfulness
    of his acts
  • Crimes must show intent- the insanity plea
    removes intent

Steps in Pursuing Justice
  • Sometimes, the DA will plea bargain with the
  • The defendant works out a deal with the DA
  • May reduce jail time

Types of Crimes
  • All crimes are violations (breach of a right,
    duty, or law)
  • 3 types
  • Infractions
  • Misdemeanors
  • Felonies

  • Minor offense or petty crime
  • Is less serious than a misdemeanor
  • Examples include
  • Jaywalking
  • Traffic violations
  • Littering
  • Penalty is usually a fine

  • Cases are tried in court
  • Punishable by no more than 1 year in jail
  • Examples include
  • A first offense of drunk driving, vandalism,
    shoplifting, simple assaults, trespassing, or
  • Fines range from less than 250 to 2500
  • Community service is also part of the sentence

  • Cases are tried in court
  • Punishable from 5 years to life
  • Some states offer death penalty
  • Examples include
  • Arson, aggravated assault, burglary, robbery,
    homicide, and rape
  • Fines may be up to 100,000
  • Probation may also be determined

Federal Rules of Evidence
  • Probative
  • In evidence law, tending to prove something
  • Material
  • In evidence law, relevant and significant.
  • Hearsay
  • Testimony given by a witness who relates not what
    he or she heard, saw, or knew personally, but
    what others have said
  • Is not admissable in the court of law

Admissibility of Evidence
  • 1923 Frye v. US
  • Scientific evidence is allowed into the courtroom
    if it is generally accepted by the relevant
    scientific community.
  • The Frye standard does not offer any guidance on
  • The evidence is presented in the trial and the
    jury decides if it can be used.
  • 1993 Daubert v. Dow
  • Admissibility is determined by
  • Whether the theory or technique can be tested
  • Whether the science has been offered for peer
  • Whether the rate of error is acceptable
  • Whether the method at issue enjoys widespread
  • Whether the opinion is relevant to the issue
  • The judge decides if the evidence can be entered
    into the trial

Facets of Guilt
  • Try to prove
  • Means- person had the ability to do the crime
  • Motive- person had a reason to do the crime
  • Does not have to be proved in a court of law
  • Opportunity- person can be placed at the crime