The Nature Of Evidence

Question 1

What are the 5 factors affecting persistence of evidence?

Answer 1

1. Types of evidence
2. Location of evidence
3. Environment
4. Time from transfer to collection
5. Activity around evidence

Question 2

Define the term ‘persistence of evidence’

Answer 2

The ability of transfer from evidence to remain in that location until further transfer

Question 3

What is the difference between direct and indirect transfer?

Answer 3

DIRECT - movement of an item from the source to the recipient
A -> B

INDIRECT - intermediate object that conveys the item to the recipient
A -> B -> C

Question 4

What are the 5 factors affecting transfer?

Answer 4

1. Pressure
2. Number of contacts
3. How easy it transfers
4. Form/structure of object
5. Surface area involved in contact

Question 5

Define Locard’s principle

Answer 5

When two things come into contact information is exchanged/transferred

Question 6

Define the term ‘Evidence’

Answer 6

Information that is given in a legal investigation to make a fact or proposition more or less likely

Question 7

Describe the difference between class and individual evidence

Answer 7

CLASS - placing evidence into a group of objects with similar characteristics

INDIVIDUAL - categorising an item in a set or class that has one and only one member

Question 8

Describe the difference between questioned and known evidence

Answer 8

QUESTIONED - evidence found however source of origin isn’t known

KNOWN - evidence in which the source of origin is known

Question 9

What are the 4 types of controls used for analysing evidence?

Answer 9

POSITIVE - running a presumptive test on a known sample yielding a positive test

NEGATIVE - running a test where nothing should show up yields a negative test

FALSE POSITIVE - when a negative control is not used = concludes that the stain is something when it isn’t (TYPE 1 ERROR)

FALSE NEGATIVE - when a positive control is not used = concludes that the stain isn’t something when it is (TYPE 2 ERORR)