Trace evidence

Question 1

Types of trace evidence:

Answer 1

Fibres
Fingerprints
Body fluids - blood, semen,
Hairs

Question 2

Fingerprints

Answer 2

Classification:
-ridges and patterns
(Loops, arches, whorls)

Question 3

LOOPS-Fingerprints

Answer 3

The most common type
2 groups (direction of slant)
-Ulnar loop -most common
-Radial loop (slants towards radius- thumb side of hand)
-Directions of loops will be opposite on the opposing hand

Question 4

ARCHES-Fingerprints

Answer 4

Simplest type of fingerprint
Can be divided into two groups:
-Plain arch - mound-like pattern
-Tented arch -spike/tent

Question 5

WHORLS-fingerprints

Answer 5

4 groups:

• Plain whorl - circular spiral pattern
• Central pocket whorl- a tight circular pattern in the centre of the fingerprint
• Double loop whorl - two looped patterns
• Accidental whorl - an irregular shaped circular pattern

Question 6

Identifying a print

Answer 6

-Crime scene
-types of fingerprint
-latent
-visible
-plastic
ACE-V
-analysis
-comparison
-evaluation
-verification

Question 7

Targeting potential traces

Answer 7

Reactive - know what fibres to look for
or
Inceptive - have trace fibres & need something to link it to

Question 8

Recovery of evidence (in lab)

Answer 8

Shaking, brushing, taping, vaccumming, swabbing, hand picking

Question 9

Glass

Answer 9

colour/thickness
physical analysis - index-refractive
chemical analysis
fracture patterns

Question 10

Fibres

Answer 10

Any long thin flexible solid material

analysis: taping;microscopy;microspectrophotometer;TCL thin layer chromotography; infared spectroscopy

Question 11

Hair

Answer 11

Medulla, cortex, cuticle

sources & classification

Question 12

Assessment of significance

Answer 12

Extent of comparison
Rarity of trace material
Expectations
Combination of evidence
Alternative innocent sources
Contamination

Question 13

Reliability

Answer 13

Reputable
Relevant circumstances
Funding