Chapter 4: Physical Evidence Flashcards
CHaracteristics of physical evidence that are common to a group of objects or persons are termed:
Class Characteristics
*Soil, glass
Evidence with _______ can be identified, with a high degree of probability, as originating with a particular person or source.
Individual Characteristics
Three types of unknown or questioned samples:
- Recovered crime scene sample who is the source is in question.
- Questioned evidence that may be transferred to an offender during the commission of a crime and has been taken away by him or her.
- Evidence from an unknown or questioned source that can be used to link multiple offenses.
The three types of known samples are:
- Standard or reference sample.
- Control or blank samples.
- Elimination sample.
An _______ is taken from a source know to have had lawful access to the crime scene such as a police officer, medical technician, or occupants.
Elimination Samples
There is growing evidence that within soil, there are _______ that essentially create their own distinctive DNA signatures.
Microbial Communities
Soil consists of loose aggregates of accumulations of natural elements, such as:
- Rocks
- Bacteria
- Minerals
- Pollen
- Fungus
- Plant Material
_______ is the discipline that studies pollen and spores.
Forensic Palynology
Despite the fact Forensic Palynology can be a powerful investigative tool, it is extremely _______ because it is labor-intensive and requires considerable expertise and experience.
Underutilized
Collect soil samples at a depth consistent with the depth at which the questioned soil may have originated. In most cases, samples will be a _______ of material taking no more than _______ from the surface.
a. Tablespoon
b. 1/2 inch
Do not remove soil adhering to shoes, clothing, and tools. Do not process tools for latent prints at this time. _______the soil garments.
Air Dry
Soil garments should be packaged separately in _______.
Paper Bags
_______ are often present at crime scenes and overlooked by investigators.
Shoe and Tire Impressions
The two major categories of impression evidence are:
- Surface Impressions
2. Three-Dimensional Impressions
_______ impressions are two dimensional. They have a length and width and by definition, lack any appreciable height. They are often called “prints” or “residual prints”.
Surface Impression
_______ should be used to lift dry dust or dry residue surface impressions from clean porous or non-porous surfaces.
Electrostatic Dust Print Lifter
_______ work well for lifting surface impressions are non-porous surfaces that have been enhanced with fingerprint powder.
Adhesive and Tape Lifters
On porous or non-porous wet or dry surfaces, black white, or transparent _______ are good performers.
Gelatin Lifters
_______ is used for casting powdered surface impressions, particularly on textured or uneven surfaces.
Mikrosil Forensic Silicone
_______ are positioned directly over the surface impressions and captures detailed digital images for comparison use.
Electronic Shoe Print Scanner
_______ that have a significant depth, in addition to having a length and width.
Three Dimensional Impressions (3DI)
_______ is an effective method of collecting three (3DI), and they should always be photographed prior.
Casting
A _______ may be used to “fix” the details, taking care not to destroy them as it is applied.
Silicone Release Agent or Hairspray
When preparing Dental Stone, mix _______ pounds of dental stone and _______ ounces of water before massaging it is a gallon freezer bag for _______ minutes.
a. 2
b. 10-12
c. 3-5
Pour Dental Stone mixture _______ the impression and allow it to flow or spill over the impression as opposed to pouring it directly on the impression.
Alongside
On a warm day dental stone will dry in _______ minutes and longer when it is cold.
20-30
When the cast is firm but still soft, identifying marks can be scratched into the back. A good practice is to also indicate on the cast the _______.
Direction of North.
If an impression is frozen, use a _______.
Colored Spray Paint
When working with impressions, if the snow is soft or slushy, use a _______ to keep the snow from collapsing when you add the dental stone.
Snow Print Wax
_______ has long been used o cast impressions in snow.
Sulfur
Paint evidence is transferred as _______, _______, or “_______” from old, dry paint.
a. Fresh Smears
b. Dried Chips
c. Chalking
Most commonly paint transfers from one source to another in:
- Burglaries
2. Hit & Run Accidents
Standard paint evidence samples should be the size of a _______.
Nickle
One rule of thumb while collecting paint samples, is to collect _______ such samples around each area involved, which should be packaged individually.
Four