ETC Trace Evidence 3

Question 1

What is cross-contamination in the context of trace evidence collection?

Accepted Answer

Transfer of material between unrelated samples during collection or analysis

Answer

Exposure of evidence to rain or humidity

Answer

Mixing of biological and chemical evidence types

Answer

Using the same technician to handle multiple types of evidence

Question 2

Paint transfer evidence from a hit-and-run scene is best characterized using which combination of analytical methods?

Accepted Answer

FTIR spectroscopy and scanning electron microscopy with EDX (SEM-EDX)

Answer

Visual comparison and simple chemical tests

Answer

UV-Vis spectrophotometry alone

Answer

Standard optical microscopy only

Question 3

What is the forensic significance of finding bi-directional trace evidence transfer between two individuals?

Accepted Answer

It strongly suggests direct physical contact between the two individuals

Answer

It indicates the evidence was planted or staged

Answer

It proves guilt beyond a reasonable doubt

Answer

It shows the samples are contaminated and unusable

Question 4

When collecting fire debris from an arson scene for accelerant analysis, what type of container should be used?

Accepted Answer

Airtight metal cans or heat-sealed nylon bags

Answer

Paper evidence bags to allow gases to escape

Answer

Standard plastic zip-lock evidence bags

Answer

Glass bottles with loosely capped lids

Question 5

Which microscopic feature of hair is used by forensic analysts to estimate the racial ancestry of the contributor?

Accepted Answer

Cross-sectional shape and distribution of melanin pigment granules

Answer

Total hair length and natural color

Answer

Root morphology alone

Answer

Medullary pattern alone

Question 6

How should an evidence technician handle clothing items suspected to contain trace evidence?

Accepted Answer

Package each item separately in paper bags and avoid shaking or folding unnecessarily

Answer

Shake each item outdoors to remove loose debris before packaging

Answer

Place all items together in one large evidence bag

Answer

Wash items with distilled water to prevent microbial degradation

Question 7

What is the primary forensic value of botanical trace evidence such as pollen grains, seeds, or plant fragments?

Accepted Answer

Can associate a person, object, or vehicle with a specific geographic location or environment

Answer

Determines the precise time of death of the victim

Answer

Identifies the type of weapon used

Answer

Establishes the victim's identity through DNA