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Chapter 1
Overview of Forensics
© 2012 Cengage Learning. All Rights Reserved
“In school, every period ends with a bell. Every sentence ends with a period. Every crime ends with a sentence.” - Stephen Wright, comedian
Forensic Science
o The study and application of science to mattersof law
o Includes the business of providing timely, accurate, and thorough information to all levels of decision makers in our criminal justice system
o The word forensic is derived from the Latin forensis meaning forum, a public place where, in Roman times, senators and others debated, performed, and held judicial proceedings.
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Forensic Scientist
o A forensic scientist studies and analyzes physical evidence used in criminal court cases.
o Many accused criminals are found either innocent or guilty based on the strength of evidence that a forensic scientist provides.
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© 2012 Cengage Learning. All Rights Reserved
4 Forensic Science II: Overview of Forensics, Chapter 1
© 2012 Cengage Learning. All Rights Reserved
Historical Development (Obj 1.2)
o Alphonse Bertillon (1853–1914) — developed the first method of criminal identification
o Sir Edward Richard Henry (1850–1931) — developed a fingerprint identification system that categorized fingerprints by whorl, loop, or arch pattern
o Karl Landsteiner (1868–1943 — discovered blood groups
o Edmond Locard (1877–1966) — founder of the Institute of Criminalistics at the University of Lyon in Lyon, France
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Locard’s Exchange Principle
o Whenever two objects come in contact with one another, they exchange some material (dust particles, hair, dead skin cells…)
o Locard strongly believed that every criminal can be connected to a crime by dust particles carried from the scene
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Historical Development (Obj 1.2)
o Calvin Goddard (1891–1955) — invented the comparison microscope
o Rosalind Franklin (1920–1958) — studied the molecule’s structure using X-ray diffraction photography of DNA
o James Watson (1928– ) and Francis Crick (1916–2004) — using Franklin’s photography, constructed a structural model of DNA
o Alec Jeffreys (1950– ) — invented DNA fingerprinting
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A Multidisciplinary Approach (Obj 1.3)
Examples:
Forensic nurse
Forensic chemist
Forensic toxicologist
Forensic meteorologist
Forensic accountant
Each career requires training and experience but historical knowledge and the ability to utilize the most current technologies of the field.
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The CSI Team and Crime Labs (Obj 1.5, 1.6, 1.7)
The crime-scene investigation team is a team of legal and scientific experts who work together to process a crime scene and evaluate the evidence
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The CSI Team and Crime Labs (Obj 1.5, 1.6, 1.7)
Processing a Crime Scene Investigators choose the search method based on the size and location of the crime scene
Zone: building or other structure—homicide, home invasion, robbery, sexual assault, etc.
Spiral: large area, no barriers—open field—kidnapping, homicide
Line search: large area looking for a large object in a single direction—site of a plane crash
Grid: large area looking for a large object in two directions—arson investigation
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The CSI Team and Crime Labs
o Testimonial evidence — the witness testimony used to build a timeline of events
o Physical evidence —any material collected or observed at a crime scene that could link potential suspects to a crime
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Evidence
o Chain of Custody
• Provides documentation of every person who has come into contact with the evidence
• A paper trail• Demonstrates to the courts
that the evidence that is being presented at trial is free of contamination, alteration, or substitution
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Evidence
o Trace Evidence
o Reference samples
o Class characteristics
o Individual characteristics
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Physical Evidence
Transient Evidence--temporary; easily changed or lost; usually observed by the first officer at the scene
Odor--putrefaction, perfume, gasoline, urine, burning, explosives, cigarette or cigar smoke
Temperature--of room, car hood, coffee, water in a bathtub; cadaver
Imprints and indentations--footprints; teeth marks in perishable foods; tire marks on certain surfaces
Markings
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Physical Evidence (cont)
Pattern or Transfer Evidence--produced by direct contact between a person and an object or between two objects. There are several ways of classifying evidence. In this class, we will use: Biological Chemical Physical Miscellaneous
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Landmark Cases (Obj 1.8)
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Landmark Cases (Obj 1.8)
Frye v. United States (1923)
The Frye Standard — evidence, procedures, and equipment presented at trial must be generally accepted by the scientific community
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Landmark Cases (Obj 1.8)
Daubert v Merrell Dow Pharmaceuticals (1993)U.S. Supreme Court ruled that the trial judge
had ultimate decision-making power regarding expert testimony at trial1. Has it been tested?2. Has it been peer reviewed?3. What is the rate of error?4. Is it generally accepted?
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Landmark Cases (Obj 1.8)
Dr. Carl Coppolino (1963)o The court ruled
• The fact that a technique, test, or procedure is new does not necessarily mean its findings are inadmissible in court
• The expert witness is responsible for providing scientifically valid testimony to support the findings
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The Judicial Process (Obj 1.9)
o The U.S. Constitution (1787)o The Bill of Rights (1789)
• The first ten amendments to the constitution• Sixth amendment ensures that a person will be
tried by an impartial jury of his or her peers
The Judicial Process (Obj 1.9)
o Arrest - gathering evidence to show probable cause
o Observation o Expertise o Information o Circumstantial evidenceo Before the Trial — the
discovery phaseo At the Trial — prosecution
and defense present their cases
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Chapter Summary
o Forensic science is the application of science to law. o Many disciplines are utilized in forensic science.o Processing a crime scene requires a thorough and
systematic approach.o Physical evidence is any substance that can link a
potential suspect to a victim or crime
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Chapter Summary
o When processing evidence, investigators use identification and comparison tests to attempt to make connections between victims, suspects, and crime scenes.
o Evidence that possesses class characteristics can be associated with a group rather than with a specific individual.
o Evidence that possesses individual characteristics can be associated with a single person with a high degree of certainty.
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© 2012 Cengage Learning. All Rights Reserved
Chapter Summary
o A chain of custody is necessary to maintain the integrity of the evidence.
o The judicial process in the United States is based on the U.S. Constitution.
o Law enforcement personnel must prove probable cause before a judge will sign a search or arrest warrant.
o In court, a jury of the suspect’s peers hears evidence from both sides.
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