FORENSIC SCIENCE
CHAPTER 1 INTRODUCTION
Learning Objectives
• Describe how the scientific method is used to solve
forensic problems.
• Provide examples of the growth and development of
forensic science through history.
• Understand the relationship between our legal system
and prosecution of criminals.
What is forensic science?
• The study and the application of science to matters of law.
Criminology
Includes the psychological angle: studying the crime scene
for motive, traits, and behavior that will help to interpret
the evidence
So what does a crime lab look like?
• Physical science unit
Chemistry
Physics
Geology
• Biology unit
• Firearms and ballistics unit
• Document examination unit
• Photography unit
The most common types of evidence examined are drugs,
firearms, and fingerprints.
https://www.youtube.com/watch?v=bztlYwckmVE
What specialties are found in a crime lab?
• Forensic pathology
• Cybertechnology
• Forensic anthropology
• Geology
• Forensic entomology
• Environmental science
• Forensic psychiatry
• Palynology
• Forensic odontology
• Polygraphy
• Forensic engineering
• Voiceprint analysis
Federal Crime Labs
• FBI: Federal Bureau of Investigation
• DEA: Drug Enforcement Agency
• ATF: Alcohol, Tobacco, and Firearms
• USPS: United States Postal Service
• U.S. Fish and Wildlife Service
• Department of Homeland Security
• Department of the Treasury
Scientific Method in forensic science
• Observe a problem or questioned evidence and collect
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objective data.
Consider a hypothesis or possible solution.
Examine, test, and then analyze the evidence.
Determine the significance of the evidence.
Formulate a theory based on evaluation of the
significance of the evidence.
The Locard’s Principle
• Locard's principle holds that the perpetrator of a crime
will bring something into the crime scene and leave with
something from it, and that both can be used as forensic
evidence.
Criminal justice and the law
• Statutory law passed by bodies such as Congress.
Based on the Constitution.
• Common law based on judicial opinions or precedents
• Civil law based on non criminal suits to preserve
individual or civil rights
• Criminal law concerned with offenses against an
individual that are not acceptable to society
• Misdemeanor = minor crime – minor possession of drugs
• Felony = major crime such as murder
The Bill of Rights Guarantees;
1. Presumed innocent until proven guilty
2. Not to be searched unreasonably
3. Not to be arrested without probable cause
4. Against unreasonable seizure of personal property
5. Against self-incrimination
6. To fair questioning by police
7. To protection from physical harm throughout the justice
process
8. To an attorney
9. To trial by jury
10. To know any charges against oneself
Steps in pursuing justice
• Miranda rights – police must inform arrestees that they
have the right to remain silent and a right to an attorney.
• Steps involved in court cases
1. Arraignment – defendant hears charges and enters plea
2. Evidentiary hearing – evidence presented and charges
filed or dismissed.
3. Grand jury decides whether to indict
4. Plea bargain – a defendant pleads guilty in return for a
lesser charge
Admissibility of Evidence
• Evidence must be probative (must prove something. Hearsay
is inadmissible.
• The Daubert Ruling – used mostly in federal courts
• The judge decides if the evidence can be entered into the trial.
Admissibility is determined by:
1.
Whether the theory or technique can be tested
2.
Whether the science has been offered for peer
review
3.
Whether the rate of error is acceptable
4.
Whether the method at issue enjoys widespread
acceptance
5.
Whether the theory or technique follows standards
Key Vocabulary terms
• Criminalistics
• Evidence
• Forensics
• Pathology
• Entomology
• Odontology
• Toxicology
• Locard Principle
• Criminal law
• Civil Law
• Misdemeanor
• Felony
Probable cause
Miranda rights
Arraignment
Grand jury
Indict
Probative
Arson
Hearsay
Expert witness
Frye Standard
Daubert ruling/Junk science