Introduction to Forensic ScienceChemistry 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 Sciencethe 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 2. Fingernail scrapings

3. Hairs 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