From the second a crime is committed
traces of the crime are left in the environment.
The location where a crime took place can be full of physical evidence
which can link the crime to the criminal
and ultimately assist the police in their investigation.
This location is known as the crime scene.
Crime scenes can be anywhere, indoors, outdoors,
a business premises, domestic dwellings or vehicles
and no two are ever the same.
The work of the crime scene investigator, or CSI,
is a key part of processing a crime and obtaining evidence.
For this reason alone
the skills they need
and the procedures they follow are of vital importance.
Before a CSI even enters a crime scene
they need a full set of appropriate protective clothing.
The full crime scene suit,
sometimes called a bunny suit,
consists of boot covers, gloves, a hood and a mouth guard.
This clothing will protect the CSI
and ensure they do not contaminate the crime scene.
Crime scenes often occur outside
and a police officer is usually the first person at the scene.
However, the police officer should not disturb the crime scene
and should instead set up a cordon
to protect the evidence contained within.
When the crime scene investigator
enters the crime scene
they will use the common approach path.
This is a path from the edge of the cordon
to the focal point of the crime scene
and in most cases
stepping plates will be used along this path
to preserve the evidence.
When available these stepping plates should be used at all times.
A CSI’s job
is to both accurately document and process the crime scene.
Documenting the scene involves taking photographs of the crime scene,
of exhibits
and taking notes.
Documenting the crime scene will continue
as they start to collect the evidence.
As the crime scene is processed
the CSI has to be very conscious of environmental factors
which may compromise the evidence.
This is especially important in outside crime scenes
as factors such as rain,
snow and strong wind
can mean the need to collect the evidence faster than normal
or erect temporary structures to protect the evidence.
The crime scene may also need to be protected
if it is near a public area
where the media or passers-by can see it.
Time of day can also play a major role in how a crime scene is processed.
In some instances it may be advisable
to preserve the scene until natural light is available.
However in many cases temporary,
high powered lighting rigs
and powerful torches
can be used to process the scene.
Indoor crime scenes have their own set of issues
whether it’s a business property or a domestic dwelling.
In indoor crime scene such as burglary,
the CSI may have to speak to a victim of crime.
In such cases they should be empathetic
and have good communication skills.
They must also be considerate of person environments
and balance the respect for someone’s property
with the need for a thorough scientific examination.
In more serious crimes
it may be more necessary
for the CSI to remove objects and furnishings from the property.
Another common crime scene is vehicle crime.
These are processed like any other crime scene.
However in less serious crime such as car theft
the CSI will focus their efforts on the point of entry
such as a broken window.
In more serious crimes
the car can be stripped to look for evidence
this would include lifting the carpets,
taping the upholstery
and analysing the lifts for trace forensic evidence.
As you can see,
crime scenes are very varied
and take place in a wide range of locations.
However they do have a number of basic principles
in common
including cordons,
common approach paths
and the systemic recovery and collection of evidence.
The crime scene investigator has a key role in documenting the crime scene
and collecting the physical evidence
left during a crime.