Crime Scene
Who is the first person at the crime scene?
Responding officer
What are the 3 layers of hair?
Cuticle (outer layer)
Cortex (middle layer)
Medulla (inner layer)
What are the 2 general types of fibers? Explain each
Filament type- long, continuous fibers
Staple type- short fibers twisted together
What are the 3 layers of skin?
Epidermis (outer layer)
Dermis (inner layer)
Papillae
What is an imprint and what is an impression?
Imprint- 2D prints made in a hard material (bloody footprint on a hardwood floor)
Impression- 3D prints made in a soft material (mud, sand, snow)
This document contains the location of a piece of evidence at any given point and every person who handled the evidence
Chain of custody
What are the different phases of hair growth?
Anagen- active growth phase
Catagen- transitional phase between anagen and telogen
Telogen- resting phase, hair becomes a bulbous shape, falls out easily and returns back to the anagen phase
What are the 3 types of natural fibers?
Plant, animal and mineral
Before the discovery of fingerprints, what method was used as a means of identification?
Bertillonage
Besides footwear, what are 3 other types of impression evidence?
Tiremark, bitemark and fingerprints
What are the 2 types of sketches and how are they different from one another?
Rough sketch is done at the crime scene and is NOT drawn to scale
Smooth sketch is done in the lab and IS drawn to scale
If a hair was forcibly removed, what will be present on the hair?
Follicular tag
What are the 3 collection methods for fibers and how are they packaged?
Pluck, tape, vacuum; coin envelope and druggist fold
What are the 3 general patterns of fingerprints? Explain each
Loop- ridges enter one side and exit the SAME side
Arch- ridges enter one side and exit the OPPOSITE side
Whorl- similar to a spiral
What are 3 methods for casting impressions in snow?
Highlighting with colored aerosol spray, Snowprint Wax with dental stone, Sulfur Casting
What are the 2 types of evidence testing? Explain how they are different
Presumptive testing- A quick screening test usually performed at a crime scene, Only gives an INDICATION that the compound of interest is present
Confirmatory testing- Conclusively identifies the sample
What are 2 methods performed to detect drugs in hair?
ELISA and GC/MS
What is the ONLY naturally occurring mineral fiber?
Asbestos
What are the 3 types of fingerprints? Explain each
Latent prints- not readily visible to naked eye
Patent prints- readily visible to naked eye
Plastic prints- impressed into a soft surface
Give 3 examples of class characteristics for footwear imprints/impressions
Manufacturer, type of shoe, model and size
How should the following pieces of evidence be packaged:
1. Bloody sweater
2. Fibers and hairs
3. Arson debris
4. Weapons
1. Paper bag
2. Paper bindle (druggist fold) or coin envelope
3. Airtight container (paint can)
4. Cardboard box
What are 5 characteristics that can be determined by examining a hair microscopically?
Species of origin
Somatic origin
Racial origin
Common origin between a questioned and known sample
Whether the hair was naturally shed or forcibly removed
Presence of artificial treatment
Disease/damage
What device is used to produce fibers?
Spinneret
What is the fingerprint database called and what does each letter stand for?
Automated Fingerprint Identification System (AFIS)
What are 2 development methods for latent imprints and 2 development methods for plastic impressions?
Latent- electrostatic lifting and luminol
Plastic- plaster of Paris/dental stone, aerosol sprays, sulfur casting