CRIME SCENE INVESTIGATION
1. Introduction
What is crime scene investigation?
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this is seemingly a trivial question with an obvious answer
investigation – the study of something, gathering information, making conclusions
crime scene – the place where the illegal event occurred
Is this a satisfactory definition?
If not, why not?
Exercise 1.1
a)
Can you think of any reasons why the definition of crime scene is inadequate?
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not all relevant evidence is found exactly where the incident occurred
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examples – trace evidence on criminal’s clothes, discarded weapons,
Lockerbie
the term crime isn’t really appropriate because not everything that must be
investigated is actually a crime – incident is better
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examples – suicide, car accidents
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Exercise 1.1
b)
What is a more useful definition of “crime scene” for our purposes?
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all locations related to the incident where evidence may found
Example - Lockerbie
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Dec.21, 1988 – Pan Am flight 103 from Frankfurt to New York exploded midair
over Scotland
the largest pieces landed on the Scottish village of Lockerbie
all 259 on board died, as well as 11 on the ground
Lockerbie
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the debris was spread out over a 300 km path, an area of 2000 sq. km
Lockerbie
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the cause of the explosion was determined
to be the result of a bomb in a suitcase in
the luggage hold
the suitcase was unaccompanied, meaning
that the person(s) who checked it in did not
travel on the plane with it
This incident sparked one of the largest
international investigations before
September 11
The British Army began the task of covering
the area, marking sites, making notes
the job of collecting forensic evidence came
later
Lockerbie
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one searcher told of finding a body, absolutely intact, sitting seemingly calm, still
strapped into his airplane seat
thousands of bits of Boeing 747 were taken to a warehouse and pieced together,
until they made what almost looked like an aircraft
The nature of crime scenes
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large, small or in-between
the incident will always be serious for at least one person, regardless of whether
an outsider might consider it trivial
it may be in a mansion or a sewer
the evidence for investigation might be bits of glass or a three week-old rotting
corpse covered in maggots
it will never be a happy scene
it might be a job for you but remember to treat the victim as a human with
feelings!
Exercise 1.2
1.
2.
3.
4.
5.
6.
7.
8.
police response
evidence collection (testimonial & physical)
investigation by police/analysis of evidence by forensic lab
arrest of suspect
charging of alleged criminal
trial
conviction or acquittal
appeal
Exercise 1.3
Secure
Interpret
Present
Evaluate
Analyse
Document
Collect
Types of crime scenes
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affects the evidence gathering process
most important are:
 location
 nature of incident
Exercise 1.4
interior vs exterior
 ability to seal off the area
 security of evidence
 confined spaces
 need to allow public access within a
reasonable timeframe
size
 problems of security
 time and number of people required to
search
geographical location
 time taken to get people and equipment
to scene
 difficulty in access
prevailing conditions
 difficulty in finding & preserving evidence
person (dead or alive)
 need for sensitivity
Nature of incident => evidence gathering
process
 priority order for allocating resources
Evidence types
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impression – marks left in or on a surface, e.g. fingerprints
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biological – material from a natural (human, animal or plant) source, e.g. blood
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trace –small pieces of a range of materials, transferred by person to crime scene
or vice versa, e.g. glass fragments
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weapons
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documents – including electronic forms, e.g. stolen credit cards
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miscellaneous items – objects that don’t fit into the above categories, e.g. stolen
merchandise
EXERCISE 1.6
In the list of evidence types in Table 1.1 are a number described as standards. What
does this mean?
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samples taken for comparison with evidence recovered from crime scene
e.g. blood & fingerprints from suspect
EXERCISE 1.7
What evidence types would you look for in a car theft?
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fingerprints
tool marks
footwear impressions
tyre patterns
hair
fibres