Lecture 3 - Forensic Science and Crime Scene Investigation

Question 1

What kind of things can you leave behind?

Answer 1

Hair 
fibre 
DNA 
Fingerprints 
other contaminants such as pollen 
foot prints

Question 2

Every contact …

Answer 2

leaves a trace

Question 3

Forensic science =

Answer 3

science used in the court of law

Question 4

Lockard’s exchange princlple =

Answer 4

every contact leaves a trace

Question 5

Forensic evidence can be used to

Answer 5

dentify an offender; link suspect to victim; link suspect to scene; reconstruct a sequence of events

Question 6

Crime triangles…

Answer 6

Crime triangles - all three legs support physical evidence or support the victim, suspect and scene being in that place

Question 7

Initial action (crime scene)

Answer 7

Preserve life
Make sure it is safe, this is paramount
Someone in danger comes first, they must be put in a safe environment first

Risk assessment - electrical, fire, roof collapse etc.
Consider if structure is still safe

Call for additional units- How much more man power is required?

Question 8

Initial assessment (crime scene)

Answer 8

Preserve the scene (protect from contamination) 
Cordons (physical barrier), scene guard 
Weather protection 
Common approach path 
Zones - cold, warm and hot 
PPE requirements

Question 9

During the initial assessment by the first officer at the scene, they must ascertain whether any of the following are present or nearby…

Answer 9

Injured persons
Victims
Eyewitnesses
Suspects

Question 10

Initial assessment - Preserve the scene from contamination

Answer 10

Avoidance of any unnecessary damage to the physical evidence present at the scene, this evidence is most likely to be found at the location(s) within the scene at which the crime(s) took place and along any path taken through the scene by the perpetrator(s) and possible the victim(s)
Avoid leaving fingermarks at scene
Saving lives takes precedence over both the arrest of a suspect and the preservation of physical evidence
There are two principal potential agents of damage from which the physical evidence present must be protect, namely people’s inappropriate actions and the weather - try to isolate the physical evidence from these factors

Question 11

Initial assessment - cordons (physical barrier), scene guard

Answer 11

In many cases the cordon/barrier is either absent or does not fully encompass the scene —> under these circumstances a barrier made of police plastic tape is usually sufficient

The cordoned area should include as wide an area a practical. Certainly, it should include the location(s) in the scene where the crime(s) took place and the points of entry to and exit from the scene of the people involved in the incident
In serious crime cases, it is important that the cordon around the perimeter of the scene is policed at all times

Weather protection - An assessment of the susceptibility of the evidence to damage from the weather needs to be done

Protect from members of the public and animals coming into scene

Traffic control may also be required

Question 12

Initial assessment - common approach path

Answer 12

Take as wide a path around crime scene as possible

Going in and out of the scene the same way so that you are disturbing the crime scene as little as possible = common approach path

Common approach path = a path that is made between the police cordon encircling a crime scene and the scene’s focal point (e.g. the body) in order to gain early and controlled access to the focal point

Question 13

Initial assessment - zones

Answer 13

In the case of the ram raid example
Hot zone = store, and car
Warm zone = place where things go to before they go into the scene, minimises disruption, ensures things are clean so that DNA can be found
Cold zone = support zone, not the crime scene, can be used for planning area/break area/meeting area, media and family are usually situated in this area

Question 14

Initial assessment - PPE requirements

Answer 14

Mask, hairnet, booties, double gloves, disposable suit
This kit is worn in order to avoid contamination of the evidence with material (especially DNA) derived from the person who was collecting it

Question 15

Common approach path

Answer 15

Common approach path = a path that is made between the police cordon encircling a crime scene and the scene’s focal point (e.g. the body) in order to gain early and controlled access to the focal point

Question 16

Reconnaissance (scouting)

Answer 16

Walk through scene
Usually when other experts and detectives are there and walking through
Once zones have been made

Gather information (CCTV; Witnesses)
Gather as much information as possible and then start looking at physical trace evidence - starting with DNA (the one item that is most likely to be contaminated so is usually the focus of their intention) and then working through blood, fingerprints, footprints and then food wrappers etc and the physical exhibits often come last because they are the most durable

Question 17

Primary reconstruction

Answer 17

Initial hypothesis - Were they looking for product? Looking for till? Part of a ring?

Discuss with other experts present

Question 18

Forensic strategy

Answer 18

Formal or informal plan
Formal = something you go to a lot, certain things you want to do, time is not a factor (people aren’t there)
Informal = if people are still there/in the area, things can change at any time, focus on the most important thing first, if you have to leave scene ensuring that it is protected so that you can come back to it
Even the most formal of plans are subject to change

Resources – people; equipment

Review options and order of examination

Question 19

formal plan

Answer 19

Formal = something you go to a lot, certain things you want to do, time is not a factor (people aren’t there)

Question 20

informal plan

Answer 20

Informal = if people are still there/in the area, things can change at any time, focus on the most important thing first, if you have to leave scene ensuring that it is protected so that you can come back to it

Question 21

Scene examination

Answer 21

Photograph and document the scene
Photographers come in early, allows for a reference point since they photograph it early and before the scene has been manipulated too much
Documenting the crime scene is done by making written notes that are augmented by photographs, video recordings and/or sketches as appropriate
Ensure it is noted how the physical evidence was found at the scene and the condition that it was in
Documentation might need to be used in court (if the case culminates into a trial) so needs to be good
It is important to record fragile physical evidence before it is recovered in case it is destroyed during the recovery process
All notes must be sufficiently clear and detailed to be of value to someone reading them a long time after the scene was processed
Crime scene sketches can be made or a computer can be used to generate a virtual reconstruction of the crime scene

Carry out forensic examination
Visual searching
Chemical testing of suspect stains (if required) - Usually blood, Anything else suspicious that looks biological also noted

Collection of evidence

Document evidence collection
Need a good record of things
Important for court

As more information comes to light:
Update reconstruction- Update until you have a pretty good idea of what may have happened

Question 22

Scene examination order …

Answer 22

Initial action 
Initial assessment 
Reconnaissance 
Preliminary reconstruction 
Forensic strategy 
Scene examination

Question 23

Forensic photography

Answer 23

Digital photography useful for rapid and effective image manipulation, can enable the overlapping of photographs
Digital photography can facilitate image enhances (give clarity), however the ease with which digital images can be manipulated means that their credibility in court may be diminished compared with conventional photographs
Video can be used to augment still photography in the recording of the overall appearance of a scene and the position of items of evidence within it
Scale is important to include in forensic photography
Still photographs can show the overall appearance of the scene
Each item of physical evidence that is found at the scene of a serious crime should be photographed before it is recovered or otherwise moved i.e. in situ - then can be photographed again in the lab with scale for better analysis
Photographs can also be used to preserve fragile pieces of evidence that might be damaged during their recovery
When a dead body is present at a scene, it should be photographed from several different angles using medium-range shots, close up shots of the injuries should also be taken
3D imaging systems are an emerging technology

Question 24

Serious crashes

Answer 24

Varying severity

Example: Passenger burnt - identified with wallet, visual identification impossible so have to start backwards

Question 25

Bomb threat

Answer 25

Studio - Photograph on scene (in place found) then photograph in the lab

Telling a story

Good notes

Question 26

Postmortem identification

Answer 26

Fingerprint and ridges on hand can be inked and photographed to see if on database
Dental good for identification

Question 27

Macro

Answer 27

Serial No. Scratched out … Revealed serial number through sanding it down as it changes the structure of the metal itself - able to reunite item with rightful owner

Question 28

Reconstruction

Answer 28

Remake scene, compare to other ones still intact such as the cruise ship lifeboat scenes

Question 29

partner organisations - FENZ, work safe, TAIC, CAA

Answer 29

FENZ = foreign emergency NZ

Fires… Difficult to determine arson - evidence damaged or completely destroyed often as a result of the fire

Question 30

Search warrants

Answer 30

Match up to reports so that you can get the items back to the owners

Question 31

Assisting ESR

Answer 31

ESR - houses that make methamphetamine can be searched and senior crime officers can come in and help photograph and catalog these kinds of scenes

Question 32

CCTV

Answer 32

Electronic evidence is more and more prevalence

You leave a digital footprint always

Question 33

general series of events when the police are classed to a crime …

Answer 33

Fresh scene identified by witness or victim - 111 informed - police show up and freeze scene as much as possible - senior crime officer and detectives assess and determine what needs to be preserved - then may call in ESR etc