Classifying Evidence

Question 1

What are biological physical evidence types?

Answer 1

Semen
Fingermarks
Saliva
Physiological fluids
Blood
Hair

Question 2

What are non-biological physical evidence types?

Answer 2

Powder residues
Impressions
Serial numbers
Ammunitions
Soil and materials
Documents
Tool marks
Paint
Ink
Drugs
Vehicle lights
Explosives
Wood
Glass
Fibres
Textiles

Question 3

What is the importance of classification of evidence?

Answer 3

There is a difference in collection and storage of evidence depending on whether it’s biological or non-biological.

Question 4

Household dust

Answer 4

SEM image includes long hairs of cat fur, twisted synthetic and woollen, serrated insect scales, a pollen grain, and plant and insect remains.

Question 5

What is class Evidence?

Answer 5

Class characteristics enable an object to be placed into a particular category, for example, a particular brand or type.

• Common to a group of objects or person
• Associative but not individualizing
• Simply knowing the colour of a car is not as accurate as comparing two paint chips and finding a statistically significant similarity.
• Underpinned by conceptual judgments

Question 6

What is Individualistic evidence?

Answer 6

Individual characteristics are unique to a particular object and as such, are potentially useful in the identification of scene impressions.

• Can be traced to individual source
• Striations on a bullet, irregular patterns on the bottom of a shoe, fitting together of a piece of shattered glass, matching the box of plastic storage bags to an individual bag through the striations on the bag.

Question 7

What is the value of class evidence?

Answer 7

Free from human bias

Question 8

What are the problems with class evidence?

Answer 8

Nonindividualising
General opportunity for coincidence

Question 9

What can the police use to establish if crimes are linked?

Answer 9

Physical evidence and traces that are left behind from the activities of a suspect