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Introduction to Forensic Science
Chemistry 300
sci·ence
n.
a.
The observation, identification, description, experimental
investigation, and theoretical explanation of phenomena.
b. Such activities restricted to a class of natural phenomena.
c.
Such activities applied to an object of inquiry or study.
1.
Methodological activity, discipline, or study
2.
An activity that appears to require study and method
3.
Knowledge, especially that gained through experience.
Forensic Science
the application of science to criminal
investigation
Forensic Science is multidisciplinary:
Chemistry
Biology
Physics
Geology
Computer Science
Criminology
Psychology
What information can be gained from a
crime scene?
A. Corpus delicti - the essential facts of the crime
Homicide? Suicide? Sexual Assault? Was there a weapon
involved?
B. Modus operandi - the way the crime was committed
Criminal’s characteristic patterns or style of work
C. Links from crime or victim to suspect
D. Witness testimony
E. Investigative leads
Crime Scene Investigation
1. 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)
Crime Scene Investigation
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
3. Hairs
2. Fingernail scrapings
4. Blood/urine samples
5. Swabs
6. Recovered bullets, blades
7. Fibers
8. Other materials (glass, tape, soil)
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…..
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
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
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
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
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
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?)
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