ETX 20 Midterm 2

No Body Homicide Details

Used recreation of blood loss patterns and volume to determine lethal blood loss

Daubert Criteria

The evidence used in court must have a scientific basis

Arch

Loop

Whorl

Minutiae

Fine, identifying details within a fingerprint (delta, dot, etc)

Latent Fingerprint

Made by deposit of oils and/or perspiration, usually invisible

Plastic Fingerprint

An impression made by pressing into a soft surface

Visible (patent) Fingerprint

Made by a deposit of visible material such as blood or ink

An example of a knowledge based method of personal identification

Social Security number

An example of a token of personal identification

Driver’s license

An example of a biometric method of identification

DNA

Issue with fingerprinting

Not scientific, too subjective

Caliber

Diameter of the barrel of a gun

Striations

Marks or scratches on bullet that have a length, width, and height

Lands

Raised areas on the inside of a barrel of a gun left on cartridge

Grooves

Indented areas left on cartridge from the inside of a barrel of a gun

Breech Face Marks

A ‘stamp’ left on the base of a cartridge from pressure of ejection

What important components of the Homicide or Suicide case lead to the solve?

Clothing on victim, polymer trace evidence, plant trace evidence

What is the A in ADME

Absorption

What is the D in ADME

Distribution

What is the M in ADME

Metabolism

What is the E in ADME

Elimination/Excretion

Absorption Of Alcohol

Mostly absorbed in small intestine due to larger surface area and blood flow

Distribution of Alcohol

Distributed to tissues, organs, and muscles via blood

Metabolism of Alcohol

Occurs mostly in liver, changes from ethanol to acetaldehyde to acetate to increase water solubility

Excretion of Alcohol

Time and liver function cause excretion, high individual variation due to amount of protein in diet, amount of drinking, and liver function

3 Sobriety tests

One leg stand, walk and turn, horizontal gaze nystagmus

Presumptive test

test for many classes of drugs, shows positive or negative but not concentrations

ELISA

Enzyme Immunoassay (example: covid test) presumptive test

Confirmatory test

GCMS or LCMS, shows concentrations of each individual drug

Epidermis

Outer layer of skin

Dermis

Inner layer of skin

Least common fingerprint pattern

Arch

IAFIS

Fingerprint identification system, uses 10 fingers

Level 1 of fingerprint ID

Pattern configuration and ridge flow, used to exclude

Level 2 of fingerprint ID

Minutiae and combinations, used for individualization

Level 3 of fingerprint ID

All attributes of a friction ridge including shape, contours, pores

Why can we use striations to ID a gun?

No two barrels are alike

Class characteristics of firearms

Bullet, caliber, number of lands and grooves, direction of twist

Individual Characteristics of a firearm

Wear and tear over time makes it unique

Firearm analysis result where class and individual characteristics agree

Identification

Firearm analysis where some of the class and/or individual characteristics agree

Inconclusive

Firearm analysis where none of the class or individual characteristics overlap

Elimination

A direct measurement of Blood alcohol content

Blood

An indirect measurement of blood alcohol content

Urine, breath

Ethanol

Drinking alcohol

Methanol

Poisonous form of alcohol and can cause blindness

Isopropanol

Poisonous form of alcohol

Rate of alcohol elimination

.02% per hour

Gas chromatography

a separation technique that is used to separate components of a mixture, Once separated, they can be analyzed individually using a Mass spectrometer

Mass spectrometry

Describe mass of compound, Unknown sample is compared with known standard or database of knowns. Used to identify specific drug

Methamphetamine color change

Orange to brown or strong blue

MDMA color change

Black or strong blue

Tar heroine color change

Purple

Cocaine Colbalt test

Blue flaky precipitate

Duquenois reagent Marijuana color change

Purple color change when chloroform is added