end of semester test

Question 1

Briefly describe the responsibilities of a CSI at a crime scene. In your answer include other personnel a CSI may need to liaise with at a crime scene

Answer 1

• scientific support team for the police force

Question 2

explain the attributes of a) a good crime scene photograph and b) a good photograph of an exhibit

Answer 2

crime sene

exhibit ; 3 shot rule - close up , intermediate and distant

Question 3

explain the role of accreditation and validation of methods used in fingermark enhancement and comparison

Answer 3

these

Question 4

as a CSI examining a crime scene , briefly explain how you would recover a laptop from a crime scene and what measures would be taken to preserve it’s integrity and continuity as an item of evidence

Answer 4

you would
take photos
if turned off , dont turn back on
if turned on, remove power source so that stuff c
ideally do not look through the computer unless its a cased of high importance e.g. someone is missing
put into a cardboard box

Question 5

give three examples of ways in which contamination could occur at a crime scene and the anti contamination procedures you would put in place to minimise and/or eliminate the contamination occurring in each case

Answer 5

could accidentally leave one of your own hairs, inadvertently touching a weapon and adding fingermarks , adding footwear marks
wear a hair net , wear overshoes and wear two sets of gloves at all times

Question 6

explain the ways in which you would document a crime scene, and in each case discuss the importance of that method

Answer 6

take photographs of the room to show how everything is situated(take photogrpahs looking in from each corner)
measure the size of the room and draw a floor plan
for each exhibit, do a 3 shot rule (close up, intermediate and distance) making sure to record the measurements of the exhibit.
in your crime scene notes, note anything that seems suspicious , e.g. drink cans
this is all important as upon looking over the case later on, the police could find something in the photos that helps their investigation

Question 7

explain what is meant by preserving the integrity of a digital image and describe the measures that should be in place to ensure that is maintained

Answer 7

make sure the time and date is correct
hash value - assigns a number to an image based on pixelation. any alteration to the image affects this number
watermarks - unique digital watermark is randomly embedded into a photograph. if the image is altered, the watermark is altered

Question 8

explain the chemical composition of latent fingermarks and how this is exploited when using ninhydrin to enhance latent fingermarks on paper

Answer 8

sebaceous sweat ; alcohols, fatty acids
eccrine sweat; water, salts amino acids
ingested substances; minerals and vitamins
contaminants; blood , cosmetics
ninhydrin reacts with amines to form Ruhemanns purple