Introduction

1
Introduction

• Chapter 1

2
Definition Scope

• Science occupies an important unique role in
  the criminal justice system
• Forensic science is the application of science to
  the criminal and civil laws that are enforced by
  police agencies in a criminal justice system.

3
American Academy of Forensic Science

• 10 sections
• Criminalistics
• Engineering science
• General
• Jurisprudence
• Odontology
• Pathology/biology
• Physical anthropology
• Psychiatry Behavioral sciences
• Questioned documents
• Toxicology

• This list is not exclusive.
• It does not encompass other skills, such as
• Fingerprint examination
• Firearm tool mark examination
• Computer digital data analysis
• Photography

4
History

• The first published work relating to forensic
  science was written in 1798 by Francois-Emanuel
  Fodere (France).
• Mathieu Orfila (Spain) is considered the father
  of forensic toxicology.
• Alphonse Bertilliondevised the first scientific
  system of personal identification in 1879.
• Francis Galtonconducted the first definitive
  study of fingerprints and their classification.

5
Bertillons system of bodily measurements as used
for the identification of an individual. Courtesy
Sirchie Finger Print Laboratories, Inc.,
Youngsville, N.C., www.sirchie.com.
6
History (cont)

• Leone Lattesdeveloped a procedure to determine
  blood type from dried bloodstains.
• Calvin Goddardused a comparison microscope to
  determine if a particular gun fired a bullet.
• Albert Osborndeveloped the fundamental
  principles of document examination.
• Sir Arthur Conan Doyle had a considerable
  influence on popularizing scientific
  crime-detection methods through his character
  Sherlock Holmes.
• Holmes his partner, Dr. Watson, analyzed blood,
  fingerprints, firearms, documents long before
  their value was recognized accepted by
  real-life criminal investigation.

7
History (cont)

• Walter McCroneutilized microscopy and other
  analytical methodologies to examine evidence.
• Hans Grosswrote the first treatise describing
  the application of scientific principles to the
  field of criminal investigation.
• Edmond Locard is one of the most important
  contributors in the early twentieth century.
• Locards Exchange Principle When two objects
  come into contact with each other, a
  cross-transfer of materials occurs.

8
Modern Scientific Advances

• Procedures such as chromatography,
  spectrophotometry, and electrophoresis allow
  modern forensic scientists to identify a
  substance and connect evidence to a particular
  person and place.
• Sir Alec Jeffreys developed the first DNA
  profiling test in 1984.
• Establishment of computerized databases for
  fingerprints, DNA, bullets, shell casings

9
Crime Laboratories in the U.S.

• In 1932, the FBI organized a national laboratory
  that offered forensic services to all law
  enforcement agencies in the country.
• The FBI lab is the worlds largest forensic lab,
  performing more than one million examinations
  every year.
• At present, approximately 350 public crime
  laboratories operate at various levels of
  governmentfederal, state, county, and municipal.

10
Organization of a Crime Lab

• Labs are very diverse.
• Supreme Court decisions in the 1960s compelled
  police to place greater emphasis on securing
  scientifically evaluated evidence.
• Crime rate has increased sharply in the last 40
  years.
• The federal government has no single law
  enforcement or investigative agency with
  unlimited jurisdiction.

11
Organization of a Crime Lab

• Most states maintain a crime lab to aid local
  governments that do not have access to one.
• Four major crime labs
• FBI in Quantico, VA
• DEA
• Bureau of Alcohol, Tobacco, Firearms Explosives
  
• U.S. Postal Inspection Service

12
Basic Services of a Crime Lab

• Physical science unit
• Biology unit
• Firearms unit
• Document examination unit
• Photography unit

13
Optional Services of a Crime Lab

• Toxicology unit
• Latent fingerprint unit
• Polygraph unit
• Voiceprint analysis unit
• Crime-scene investigation unit

14
Other Services

• Forensic psychiatry
• Forensic odontology
• Forensic engineering
• Forensic computer digital analysis

15
Functions of the Forensic Scientist

• The forensic scientist relies heavily on
  scientific knowledge skill but they also need
  to defend their work in the courtroom.
• They have to present evidence to the jury
  persuade the jury to accept the conclusions
  derived from the analysis.

16
Analyzing Physical Evidence

• Physical evidence is free of inherent error or
  bias.
• The underlying principles of the scientific
  method provide a safety net to ensure that the
  outcome of an investigation is not tainted by
  human emotion or compromised by distorting,
  belittling, or ignoring contrary evidence.

17
Admissibility of Evidence

• In Frye v. United States, the court ruled that in
  order to be admitted as evidence at trial, the
  questioned procedure, technique, or principles
  must be generally accepted by a meaningful
  segment of the relevant scientific community.
• In the 1993 case, Daubert v. Merrell Dow
  Pharmaceuticals, Inc., the Supreme Court that the
  Frye standard is not an absolute prerequisite to
  the admissibility of scientific evidence under
  the Federal Rules of Evidence.
• According to the Court, the Rules of Evidence
  (especially Rule 702) assign to the trial judge
  the task of ensuring that an experts testimony
  rests on a reliable foundation is relevant to
  the case.

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Judging Scientific Evidence

• The Court offered some guidelines as to how a
  judge can determine admissibility of evidence
• Whether the scientific technique or theory can be
  (and has been) tested
• Where the technique or theory has been subject to
  peer review publication
• The techniques potential rate of error
• Existence maintenance of standards controlling
  the techniques operation
• Whether the scientific theory or method has
  attracted widespread acceptance within a relevant
  scientific community

19
Providing Expert Testimony

• An expert witness is an individual whom the court
  determines to possess a particular skill or
  knowledge in a trade or profession that is not
  expected of the average layperson that will aid
  a court in determining the truth of a matter at
  trial.
• Depending on the subject area in question, the
  court will consider knowledge acquired through
  experience, training, education, or a combination
  as sufficient grounds for qualification as an
  expert witness.
• Competency may be established by having the
  witness cite educational degrees, participation
  in special courses, membership in professional
  societies, and any professional articles or books
  published.
• The question of what credentials are suitable for
  qualification as an expert is ambiguous highly
  subjective one that the courts wisely try to
  avoid.

20
Training

• Every officer engaged in fieldwork, whether it be
  traffic, patrol, investigation, or juvenile
  control, often must process evidence for
  laboratory examination.
• Some police departments send specially trained
  evidence-collection technicians to the crime
  scene but most of the time a patrol officer or
  detective collects the evidence.