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Forensic Science


Title: Slide 1 Author: temporary Last modified by: FTIS Created Date: 7/21/2005 11:24:15 AM Document presentation format: Letter Paper (8.5x11 in) Company – PowerPoint PPT presentation

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Title: Forensic Science

Forensic Science
  • Original Powerpoint Adapted from Richard
    Saferstein Prentice Hall
  • and Mrs. Partridge LHS

  • fe-ren sik adj relating to, used in, or
    appropriate for courts of law or for public
    discussion or argumentation
  • Latin forensis public, of a forum
  • forensic science is the
  • application of science
  • to criminal and civil laws.

  • A body of knowledge concerning the recognition,
    collection, identification, individualization,
    and evaluation of physical evidence using the
    techniques of natural science in matters of legal

What a forensic scientist DOES!
  • She deals with lifes grimmest realities
    dispassionately while never losing sight of the
    feelings that keep her human

What a forensic scientist DOES
  • A forensic scientist must be skilled in applying
    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.
  • A forensic scientist may also provide expert
    court testimony.

Is it forensics?
  • The science of forensic science
  • Scientific method
  • Observing Problem
  • Researching problem survey the scene
  • Hypothesizing who committed the crime based on
  • Testing analyze the evidence to see if it
    implicates a suspect
  • If answer is wrong, start over
  • Avoid forming conclusions too early in an
    investigation. You may miss/neglect evidence.

Is it forensics?
  • Forensic Process R.I.I.R.
  • Recognition
  • Scene survey, documentation, collection
  • Identification
  • Comparison testing
  • Individualization
  • Evaluation, interpretation
  • Reconstruction
  • Reporting presentation -

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Scope of Forensic Science
  • Criminalistics the application of physical
    sciences to criminal investigation
  • Specialties
  • Medicine
  • Anthropology
  • Odontology
  • Entomology
  • Legal
  • Document analysis
  • Ballistics
  • Facial reconstruction
  • others

History of Forensic Science
  • Many believe that Sir Arthur Conan Doyle
    popularized scientific crime-detection methods
    through his fictional character Sherlock Holmes

History of Forensic Science
  • Holmes applied new, developing principles of
    serology, fingerprinting, firearm ID, and
    questioned-document examination long before their
    value for first recognized and accepted by real
    criminal investigators
  • Doyles first novel, A Study in Scarlet, has
    examples of his ability to describe scientific
    methods of detection, years before they were
    actually discovered and implemented

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History of Forensic Science
  • Forensic Science has been around nearly 900 years
  • First recorded application of medical knowledge
    to the solution of a crime was in 1248
  • 1836 - James Marsh detected arsenic poisoning in
    connection with a criminal investigation
  • 1839 - Mathieu Orfila, toxicology, perfected
    techniques to trace poisons
  • 1879 - Alphonse Bertillon developed
    anthropometry, body measurements to distinguish
  • Late 1800s - Alexandre Lacassagne, ballistics
    and bloodstain patterns

History of Forensic Science
  • 1892 Francis Galton developed
  • methodology of classifying and
  • filing fingerprints
  • 1901 Karl Landsteiner discovered blood typing
  • 1915 Leone Lattes devised a
  • simple procedure for
  • determining blood group

History of Forensic Science
  • 1910 Edmund Locard, exchange principle, 1st
    forensic science journal (Locards Exchange
    Principlestates that when a criminal comes in
    contact with an object or person, a
    cross-transfer of evidence occurs)
  • 1924 August Vollmer, LAPD crime lab (oldest)
  • 1932 FBI laboratory, fingerprints
  • 1980s DNA testing
  • ()

Forensic Science in the USA
  • Federal (FBI, DEA, secret service, ATF)
  • State (coroner, medical examiner)
  • Local (sheriffs, police)
  • Private (DNA labs)
  • Stop/warn

Coroner vs. Medical Examiner
  • Coroner an elected official with death
    investigation duties
  • Medical Examiner an appointed government
    official, always a physician and often a forensic
    pathologist, with duties of investigating sudden
    and unexpected deaths or deaths from injuries

Basic Services Provided by Crime Laboratories
  • Physical Science Unit (drugs, glass, paint, soil,
  • Biology Unit (DNA, hairs, fibers, plants)
  • Firearms Unit (ammunition)
  • Document Examination Unit (handwriting,
  • Photography Unit (all photo presentations for

Optional Services Provided by Crime Laboratories
  • Toxicology Unit (drugs, poisons)
  • Latent Fingerprint Unit
  • Polygraph Unit
  • Voiceprint Analysis Unit
  • Evidence Collection Unit

Envelope containing anthrax spores sent to
Senator Tom Daschle shortly after 9/11. A
variety of forensic skills used to examine it
Law and Science (see guided notes)
  • The philosophical foundation of the criminal
    justice system remains to PROTECT the innocent
    and to ensure that the TRUTH EMERGES for any
    matter before the court, thereby ensuring that

Bill of Rights
  • The Bill of Rights was designed to expressly
    reserve certain powers to the citizens against
    the Federal Government
  • The Bill of Rights was not always understood to
    apply to the rights of citizens when actions
    involved the state

Precedent Cases
  • Mapp v. Ohio, 1961 The 4th Amendment prohibits
    unreasonable searches
  • Robinson v. California, 1962 The 8th Amendment
    protects against cruel and unusual punishment
  • Gideon v. Wainwright, 1963 The 6th Amendment
    provides the right to counsel

Application of the Bill of Rights
  • Amendments 1 through 14 apply to all states,
  • The Federal constitution provides the minimum
    protection. The state may provide greater
    protection but not less.
  • ()

4th Amendment
  • The right of the people to be secure in their
    persons, houses, papers and effects against
    unreasonable search and seizures shall NOT be
  • No Warrants shall be issued but upon probable
    cause, supported by an Oath or affirmation,
    particularly describing the place to be searched
    and the persons or things to be seized

4th Amendment
  • The 4th Amendment requires that a valid warrant
    be issued prior to any search
  • A warrantless search is
  • Presumptively Unreasonable!

4th Amendment
  • A valid warrant is required for all unreasonable
    searches and seizures
  • Required to obtain a warrant
  • Probable cause
  • Oath or affirmation
  • Particular description area to be searched
  • What youre searching for

Evidentiary Information
  • The probable cause clause requires that the
    police establish the trust worthiness of the
    information that they base their observations
    that a crime has been committed.

Two Types of Information Sources
  • Citizen or victim
  • Both are generally trustworthy
  • No need to collaborate
  • The informant
  • Credibility of informant is important because
    informants may also be involved in criminal
    activity themselves

Two Prong Test For An Informant
  • Reliability of information
  • Established by identifying how, when, and where
    the informant received his information
  • Credibility of the Informant
  • Established by identifying the informant,
    determining his self-interest, identifying the
    past accuracy of the informant

Warrant Specificity
  • The following must also be included on the
  • Place - specific
  • Time
  • Items searching for
  • Neutral authority judges permission

Area of Protection
  • Areas of reasonable expectation of privacy
  • Car
  • Office
  • House
  • Abandoned property does not require a search

Warrantless Entry
  • Consent
  • Plain view
  • Exigent circumstance
  • Fire scene
  • Belief that a person within is in need of
    immediate aid
  • Cars parked in a public place
  • Inventory of locked areas
  • Caretaker
  • Search incident to custodial arrest
  • Arrestees clothing

5,040.00 In Hidden Compartment
Chain of Custody
  • Once the items have been seized and inventoried,
    chain of custody must be fully documented
  • Specifies who seized it, and every subsequent
    individual who has custody or control of the item

Packaging of Evidence
  • The CSI must make sure that the evidence is
    properly packaged according to the
    recommendations of the forensic laboratory
  • When evidence is presented in court, it should be
    professionally packaged and presented
  • It its necessary to repackage evidence, the
    original packaging must be included in or
    securely attached to the new package

Not like this!
Team Work
  • Forensic scientists work as members of a larger
    team, perhaps other specialized scientists, law
    enforcement investigators, prosecutors, defense
    attorneys, judges, juries and the media.

Law and Science
  • Lawyers have an OBLIGATION to conduct a spirited
    defense of the accused, especially if they are

Law and Science
  • In contrast, forensic science remains
    JUSTIFICATION based, reaching the truth,
    dependent upon evidence and data
  • All scientists are required to uphold a high
    ethical standard, bound to combine scientific
    skills with a sworn duty to the public good

Law and Science
  • From crime scene to conviction, a good forensic
    scientist will be teaching others, an ability
    that requires patience and the communication of
    complex principles in simple terms.

Law and Science
  • Frye Standard
  • (named after the 1923 case)
  • Requires the court to determine whether the
    scientific theory and/or scientific method used
    to generate evidence are generally accepted as
    reliable in the scientific community

Law and Science
  • Frye test
  • Is the scientific theory generally accepted in
    the scientific community? (experts)
  • Is the scientific method used generally accepted
    in the scientific community? (papers, books on
    the subject)
  • Has the technique been applied correctly?

Law and Science
  • Daubert v. Merrel Dow Pharmaceutical, Inc
  • Trial judges must assume the ultimate
    responsibility for acting as a gatekeeper in
    judging the admissibility and reliability of
    scientific evidence presented in their courts

Law and Science
  • Daubert Ruling Guidelines
  • Whether the scientific technique/theory can be
    (has been) tested
  • Whether the technique/theory has been subject to
    peer review and publication
  • The techniques potential rate of error
  • Existence maintenance of standards controlling
    the techniques operation
  • Whether the scientific theory /method has
    attracted widespread acceptance within a relevant
    scientific community

An Experts Role
  • By law, only a judge can declare someone an
    expert witness
  • Attorneys offer an expert witness to the court to
    give opinions within their expertise
  • Used to help clarify facts or educate the jury

Court Advice For a Forensic Scientist
  • Whereof one can not speak, thereof one must
    remain silent.
  • - Ludwig Wittgenstein