Trace evidence Flashcards
What is trace evidence analysis?
The examination of microscopic quantities of material that are of probative value in a forensic investigation.
What determines the value of different types of trace evidence?
The circumstances of the crime and how well the evidence can link the crime scene, victim, and offender.
What are the two main categories of trace evidence?
- Biological (human)
- Physical (includes biological non-human)
How can trace evidence help investigators?
It helps reconstruct the crime event and establish links between persons and scenes of interest.
True or False: Trace evidence can always be precisely analyzed.
False
What is Locard’s exchange principle?
The principle that evidence is deposited or removed during the commission of a crime.
What are the modes of transfer in trace evidence?
- One way transfer
- Two way transfer
- Direct transfer
- Indirect transfer
- Secondary transfers
What are some characteristics that can affect the transfer of trace evidence?
- Trace material
- Properties of source/recipient
- Environmental conditions
- Force, duration, type of contact
Fill in the blank: The amount and distribution of transferred evidence varies based on _______.
[location of the transferred evidence]
How does clothing material influence trace evidence transfer?
Different materials have varying abilities to repel or pick up trace evidence.
What environmental conditions can affect the transfer of trace evidence?
Conditions like rain can increase the amount of soil picked up during a crime.
How does particle size affect trace evidence?
Different sizes and shapes of particles, such as pollen or glass, can influence their transfer and persistence.
What is trace persistence?
The temporal dynamics of transferred evidence and how long it is preserved after a crime event.
What can cause the loss of trace evidence over time?
Activities of the offender, bystanders, or police, such as washing or cleaning.
What techniques are used for trace collection?
- Picking
- Scraping
- Brushing
- Combing
- Tape lifts
- Vacuum
- Swabs
What is the aim of trace analysis?
To establish points of similarity between samples and determine their rarity.
What are some properties used to classify trace evidence?
- Morphology
- Optical properties
- Physical properties
- Chemical properties
What is the priority in analytical techniques for trace evidence?
Non-destructive techniques are prioritized.
What is a compound microscope used for in trace evidence analysis?
High power examinations of samples, such as fibers or soil.
What type of microscope provides the highest magnification?
Scanning electron microscope
What is the significance of paint evidence in forensic cases?
It can indicate various crime scenes and is classified by layers, colors, and chemical composition.
How is glass evidence classified?
- Pattern matching
- Fracture shape
- Density
- Refractive index
What are the two main types of fibers found in trace evidence?
- Natural fibers
- Synthetic fibers
Fill in the blank: Soil is the most frequently transferred type of _______.
[environmental evidence]
What are the techniques used to analyze environmental evidence?
- Chemical analyses
- Physical analyses
- Biological analyses
