Warm UP

• What is Locard’s exchange principle?• _________________________• QUIZ: Monday

Crime Labs & Functions of Scientists

4 major Federal Crime Labs

1. FBI2. DEA3. Bureau of alcohol, tobacco, firearms and

explosives4. US Postal inspection service

Services of the Crime Lab

1. Physical science unit- applies techniques of chemical, physical, geology to compare evidence

2. Biology unit – DNA3. firearms unit- firearms, bullets, shells4. Document examination- handwriting5. Photogrophy unit- examine & recover physical

evidence6. Toxicology unit- body fluid & organs to

determine presence/ absence of drugs and poisons

Services (cont’d)

7. Latent fingerprint unit- process and examine fingerprints8. Polygraph unit9. Voiceprint analysis unit10. CSI unit- collect & preserve evidence

Details

• Biology Unit- dna, bloodstains, hairs, fibers, plant material

• Firearms- guns, discharge residue, weapon firing

• Documents- source of documents, paper, ink, writing samples

• Photogrophy- recording evidence, invisible information made visible.

Functions of the Forensic Scientist1. Analyze physical data2. Determing admissibility of evidence– Frye vs. U.S.- in order to be admitted as evidence at trial, the

procedure, technique or principles must be “generally accepted” by a meaningful segment of the relevent scientific community

3. Judging scientific evidence4. Providing expert testimony

“expert”- education & experienceoffers an opinion

based on training & evidece5. Furnising training in the proper recognition, collection and

preservation of physical evidence.

Review!

1. Describe a piece of evidence responsible of the physical Science Unit

2. Describe a piece of evidence responsible of the the Biology unit

3. Describe a piece of evidence responsible of the firearms unit

4. Describe a piece of evidence responsible of the photogrphy unit

5. Why should a forensic chemist be willing to testify in court

Case Analysis

1. Describe the primary issue of law whose resolution by the court was critical to the state’s ase against Dr. J

2. How did the court ultimately rule on this issue? Describe the main arguments supporting the courts decision

3. Describe the primary scientific issue raised during the trial. What were the defense’s main challenges to the scientific evidence presented by the prosecution?

4. What do you feel wre the main issues of this trial? What would you have done differently or the same?