Introduction to Forensic Science

1
Introduction to Forensic Science
Chemistry 300

• science     
• n.
• The observation, identification, description,
  experimental investigation, and theoretical
  explanation of phenomena.
• Such activities restricted to a class of natural
  phenomena.
• Such activities applied to an object of inquiry
  or study.
• Methodological activity, discipline, or study
• An activity that appears to require study and
  method
• Knowledge, especially that gained through
  experience.

2
Forensic Science
the application of science to criminal
investigation
Forensic Science is multidisciplinary Chemistry B
iology Physics Geology Computer
Science Criminology Psychology
3
What information can be gained from a crime scene?

• Corpus delicti - the essential facts of the crime
• Homicide? Suicide? Sexual Assault? Was there a
  weapon involved?
• Modus operandi - the way the crime was committed
• Criminals characteristic patterns or style of
  work
• Links from crime or victim to suspect
• D. Witness testimony
• E. Investigative leads

4
Crime Scene Investigation

• Isolate/secure the crime scene
• (establish security, boundaries, consider
  weather)
• 2. Document the scene
• (notes, photos, video, scene diagram)
• 3. Collect evidence at the scene
• (very systematic, one person in charge, preserve
  chain of evidence)
• 4. Send appropriate material to forensics lab for
  analysis
• (this is really where the lab science begins)

5
Crime Scene Investigation
6
Evidence to be examined on scene
A. splatter patterns B. fingerprints, footprints,
tire tracks C. tool marks D. firearms related
evidence
Appropriate Material to Send to a Forensics Lab
1. Clothing found 2. Fingernail scrapings 3.
Hairs 4. Blood/urine samples 5. Swabs 6.
Recovered bullets, blades 7. Fibers 8. Other
materials (glass, tape, soil)
7
American Academy of Forensic Science (AAFS)

• organized a set of rules governing the
  collection and organization of forensic evidence
• established in 1948
• divided forensic science into 9 major fields..

8
Major Branches of Forensic Science
1. Toxicology/Pharmacology 2. Serology 3.
Pathology 4. Anthropology 5. Odontology 6.
Questioned Documents 7. Psychiatry 8. Geology 9.
Engineering
9
Major Branches of Forensic Science
1. Toxicology/Pharmacology 2. Serology 3.
Pathology 4. Anthropology 5. Odontology 6.
Questioned Documents 7. Psychiatry 8. Geology 9.
Engineering
10
Major Branches of Forensic Science
1. Toxicology/Pharmacology 2. Serology 3.
Pathology 4. Anthropology 5. Odontology 6.
Questioned Documents 7. Psychiatry 8. Geology 9.
Engineering
11
Major Branches of Forensic Science
1. Toxicology/Pharmacology 2. Serology 3.
Pathology 4. Anthropology 5. Odontology 6.
Questioned Documents 7. Psychiatry 8. Geology 9.
Engineering
12
Services of a Forensics Laboratory
1. Physical Science Unit 2. Biological Science
Unit 3. Firearms Unit 4. Document Examination 5.
Photography Unit 6. Toxicology Unit 7.
Identification Unit fingerprint- voiceprint-
polygraph
8. Evidence Collection
13
Introducing Scientific Findings into Criminal
Court Proceedings
1. The Frye Test 1923 - Frye vs. United
States 2. Federal Rules of Evidence - has the
evidence/technique been tested by scientific
methodology - underlying scientific
theories/techniques have been subjected to peer
review - What is the potential error rate? -
existence of standards for the technique -
general acceptance in the scientific community 3.
Daubert standard allows the trial judge to
apply above
rules to expert witness testimony (is it reliable
and relevant?)
14
Important Scientific Advances that have
Revolutionized Forensic Science
1. Development of Photography 2. Evolution of
Chemistry as a Science / Computing Power 3.
Refinement of the Microscope 4. Advances in
Medical Pathology 5. DNA techniques