Forensic Science

•Services in the Crime Lab:–Physical Science Lab

•Chemistry, physics, geology•Drugs, glass, paint, explosives, soil

–Biology Unit•Biologists, biochemists•DNA, blood (stains), bodily fluids, wood, plant material

–Firearms Unit•Firearms, discharged bullets/casings & shells, ammo•Analysis of materials for GSR (gunshot residue)

• Document Examination Unit– Handwriting/type analysis

• Authenticity or source

– Indented writings, other anomalies

• Photography Unit– All aspects of photography

• Digital, infrared, UV, X-ray (unseen evidence)• Prepares photos for court

Extras:• Toxicology Unit (poisons/drugs)• Latent Fingerprints (hidden)• Polygraph Unit (interrogation)

• Voiceprint Analysis Unit (telephone or tape analysis)

• Crime-Scene Investigation Unit (specialize in evidence collection)

Other specializations in forensics:• Forensic Pathology (Medical Examiners):

– Who is the victim?– Injuries present– When did the injuries occur?– How were the injuries produced?– CAUSE OF DEATH

• Done by autopsy

• How is time of death determined?:

Determining Time of Death by determining stage of decomposition:

• Rigor Mortis: Muscles spend excess ATP by becoming rigid (up to 36 hours)

• Livor Mortis:– Blood settles to low points of body for first 12 hours after death– Not affected by points of constriction

• Tell position of body

• Algor Mortis– Body cools in predictable fashion until ambient (room temp)– Rule of thumb: 1 -1.5 degrees per hour (norm. cond.)

• Vitreous Humor: Potassium is released into fluid of eye in a predictable fashion

• Other: amount/cond. of food in stomach

• Forensic Anthropology: Identification and examination of skeletal remains

• Forensic Entomolgy: Study of insects and their relationship to investigation

• Forensic Psychiatry: relationship b/n human behavior and legal precedings– Competence?– Profiling

• Forensic Odentology: Teeth– Bite marks in cases– Last remaining for ID