Criminalistics Midterm

Forensic science

Deals with death, rape, forgery, fraud, negligence, assault, kidnapping

Who solves crimes?

Investigators, witnesses, interviews, and confessions

Forensic odontology

Application of dental knowledge to forensics

How can forensic odontology help?

Identify victims when body is unrecognizable

Active ingredient in marijuana

THC (Tetrahydrocannabinol)

Accidental death certificate issuer

Medical Examiner (ME)

Legal manner of death

Determined by forensic pathologist; homicide, suicide, accidental, natural, undetermined

Legal cause of death

Injury or disease that led to death

Death certificate issuer

Medical examiner or doctor

Crime scene security responsibility

First officer to arrive

Oxidation

Combination of oxygen with other substances to produce new products

Alcohol oxidation location

90% in liver, 10% in lungs and urine

Steps of alcohol oxidation

Alcohol → Acetaldehyde → Acetic acid → CO₂ + H₂O

Absorption of alcohol

Passage through stomach and small intestine into bloodstream

Factors affecting alcohol absorption

Time to drink, alcohol content, amount, food in stomach

Effect of longer absorption time

Peak blood alcohol concentration is lower

Expert witness

Only witness allowed to give opinions in their specialty

Medical examiner requirements

Board-certified physician/pathologist

Recent local crime labs processing

Drug specimens

Full-service crime lab units

Physical science, biology, firearms, document exam, photography

Duties of ME/Coroner

Determine cause/manner of death, record on death certificate

Physical evidence

Object linking crime to victim/perpetrator or proving crime occurred

Best way to package hairs/fibers

Unbreakable plastic pill bottle with pressure lid

Crime scene photographs must be

Unaltered

Minimum number of photos per scene

Four

Size of object matters in a photo

Include ruler/scale

Who advises forensic pathologist on manner of death?

District attorney

All jail deaths must be

Reported to ME/coroner, autopsied

When are autopsies required?

Deaths under suspicious circumstances

Photography alone cannot

Stand as complete evidence

Sketches of a crime scene show

Layout, evidence location, paths of entry/exit, important acts

Contact between two objects

Causes material transfer

Hair is made of

Protein keratin

Hair layers

Cuticle, cortex, medulla

Three hair growth phases

Anagen, Catagen, Telogen

Root shapes per phase

Anagen = flame, Catagen = elongated, Telogen = club

Hairs to collect for analysis

At least 25 from head or pubic region

Hair color comes from

Melanin (produced by melanocytes)

Medullary index definition

Diameter of medulla ÷ diameter of hair shaft

Medullary index in humans vs animals

Humans <1/3, Animals >1/2

Hair can show

Race, age, sex

Sex is determined from hair how

Forcibly removed hair with tissue attached

Pubic hairs

Least changed over time

Hair alterations include

Dyes, rinses, permanents, frosts, chemicals

Head hairs

Longest on human body

Define drug

Substance altering emotion, perception, behavior, or body function

Alcohol absorption: % stomach vs small intestine

20% stomach, 80% small intestine

Henry's Law

Volatile liquid in blood reaches equilibrium concentration ratios

What slows alcohol absorption

Food in stomach

Anabolic steroids do what

Promote muscle growth; reduce immune activity

Examples of club drugs

MDMA, LSD, Ketamine, GHB, Meth/amphetamine, YABA, Rohypnol, Shrooms, Coricidin

Stimulants definition

Drugs that speed up CNS

Stimulant examples

Amphetamines, cocaine

Sedatives abused by

Women and young people

GHB definition

Gamma hydroxybutyrate; depressant linked to sexual assault

Heroin origins

From opium; morphine reacted with acidic anhydride

Define toxic substance

Chemical causing damage via immediate or long-term exposure

Freebase cocaine (crack) made how

Mix cocaine HCl with ammonia/baking soda, heat

Ketamine is similar to

PCP

Psychological dependence means

Emotional need to take drug, even without physical need

Drugs causing psychological dependence

Alcohol, heroin, amphetamines, barbiturates, cocaine

Cocaine is detected where in body

Blood

Crack binds to

Paper currency ink

Trick question: Crack made of

2 parts cocaine HCl, 1 part baking soda, 20 mL water, heated until precipitate forms

Cardio-pulmonary arrest

Natural cause of death

When are fingerprints formed

Second trimester of fetal development

Three main fingerprint patterns

Loops, whorls, arches

Function of friction ridges

Grip and prevent slippage

Friction ridges found on

Palms, fingers, soles, toes