Unit 23: Forensic Evidence, Collection and Analysis
Learning aim B: Investigate a simulated crime scene using
forensic procedures.
I am a trainee Forensic Technician working for the British Transport Police’s Scientific Support
Unit. As part of my training my supervisor has set up a simulated crime scene. Me and other
trainees are to act as Crime Scene Investigators (CSIs). I will prepare appropriate documentation
to record the scene of crime, as well as collect, package and label evidence, ensuring it remains
uncontaminated and that there is a continuity of evidence. My crime of scene notes must
describe, justify, and evaluate the procedures that you used to process the scene. My supervisor
will make observations of the way I carry out the investigation. This is an assessment that will
help my supervisor decide if I am now competent to become an assistant CSI (Crime Scene
Investigators).
It is important to establish the purpose of criminal investigation:
• What – The investigators must know what the motive of committing the crime was. The
‘modus operandi’ (method of operation) is recorded because it helps law enforcement connect
different crimes regarding their similarities, helping to create a profile for the perpetrator.
• Who – The investigators need to know who the victim and who the perpetrator(s) were while
also finding any witnesses. If the victim is alive, the victim may be able to provide evidence
against the criminal; in addition, with witnesses' point of view.
• Where – The investigators must know where the crime took place and predict whether there
will be more targeted areas. In addition, investigators must try to reduce or prevent extraneous
variables from contaminating, destroying, or altering evidence linked to the scene.
• When – In order to understand the reason, the crime was committed, the investigators must
start at the beginning of it all. This may aid investigators in predicting future crimes attempted by
a perpetrator.
How to investigate a crime scene:
1. Approach and cordon off the crime scene.
2. Wear suitable PPE (Personal Protective Equipment).
3. Discuss suitable method of scene analysis.
4. Photograph evidence and important aspects of crime scene e.g., point of entry and exit,
victims' body, area etc.
5. Take notes on all details of the scene.
6. Secure and preserve evidence while also recording date, time, who took the evidence and
for what reason; for integrity of evidence.
, 7. Question any witnesses and observe security footage, if available.
Investigator roles:
Unknown 1: They were given the role of SIO (Senior Investigation Officer). Senior Investigator
Officers (SIO) oversee the whole investigation and delegates responsibilities and roles to all
authorised personnel present in the crime scene. They were responsible for questioning any
witnesses as well as ensuring the SOCO’s collected all pieces of evidence, securely packaged it,
labelled it, and described when and where they collected it.
Unknown 2: I was responsible for managing the cordon log, writing the date and time they
entered as well as time exited, their name and the reason for exit or entry. I was also responsible
for cordoning off the area to keep it secure and prevent contamination. In addition to all of that,
they were collecting evidence, packaging, and labelling it while taking photos of the scene and
evidence before it was packaged.
Unknown 3: They were responsible for sketching the evidence items and landscape/ details of
the crime scene (as well as taking measurements of each piece of evidence from the edge of the
cordon line. They were also responsible for photographing evidence, collecting evidence, and
taking notes of the crime scene. Furthermore, they were responsible for creating a bird's eye view
of the whole crime scene.
Unknown 4: They were responsible for placing evidence cards on the location of each evidence
we found and then took photographs of each evidence then packaged it while also labelling the
evidence, helped taking notes and helped in sketching the scene.
,Search methods:
Quadrant / Zone – The way this method is used is by splitting up the crime scene into smaller
sections and choosing another suitable search method to analyse the smaller zone. It is usually
used for scenes that are large or analyse a small area in an organised manner. After a period, the
investigators move to another section of the zone and analyse the same area another investigator
analysed; like a clock moving its hands around.
, Lane – An individual or group of investigators walk at the same pace in the same direction
(parallel to each other) to search for evidence. Typically used for finding larger objects in a large
area e.g., bodies in a forest.
Grid – Similar to a lane search but this covers double the area and allows different perspectives
for searching evidence on the same general path. Typically used for individuals or pairs/trios but
not large groups.
Spiral – Starting from the centre of a crime scene and spiralling outwards until the end of the
scene is reached, can be reversed, and start from the outside and work towards the centre.
Effective for single or pairs of investigators but not highly effective with groups.
Learning aim B: Investigate a simulated crime scene using
forensic procedures.
I am a trainee Forensic Technician working for the British Transport Police’s Scientific Support
Unit. As part of my training my supervisor has set up a simulated crime scene. Me and other
trainees are to act as Crime Scene Investigators (CSIs). I will prepare appropriate documentation
to record the scene of crime, as well as collect, package and label evidence, ensuring it remains
uncontaminated and that there is a continuity of evidence. My crime of scene notes must
describe, justify, and evaluate the procedures that you used to process the scene. My supervisor
will make observations of the way I carry out the investigation. This is an assessment that will
help my supervisor decide if I am now competent to become an assistant CSI (Crime Scene
Investigators).
It is important to establish the purpose of criminal investigation:
• What – The investigators must know what the motive of committing the crime was. The
‘modus operandi’ (method of operation) is recorded because it helps law enforcement connect
different crimes regarding their similarities, helping to create a profile for the perpetrator.
• Who – The investigators need to know who the victim and who the perpetrator(s) were while
also finding any witnesses. If the victim is alive, the victim may be able to provide evidence
against the criminal; in addition, with witnesses' point of view.
• Where – The investigators must know where the crime took place and predict whether there
will be more targeted areas. In addition, investigators must try to reduce or prevent extraneous
variables from contaminating, destroying, or altering evidence linked to the scene.
• When – In order to understand the reason, the crime was committed, the investigators must
start at the beginning of it all. This may aid investigators in predicting future crimes attempted by
a perpetrator.
How to investigate a crime scene:
1. Approach and cordon off the crime scene.
2. Wear suitable PPE (Personal Protective Equipment).
3. Discuss suitable method of scene analysis.
4. Photograph evidence and important aspects of crime scene e.g., point of entry and exit,
victims' body, area etc.
5. Take notes on all details of the scene.
6. Secure and preserve evidence while also recording date, time, who took the evidence and
for what reason; for integrity of evidence.
, 7. Question any witnesses and observe security footage, if available.
Investigator roles:
Unknown 1: They were given the role of SIO (Senior Investigation Officer). Senior Investigator
Officers (SIO) oversee the whole investigation and delegates responsibilities and roles to all
authorised personnel present in the crime scene. They were responsible for questioning any
witnesses as well as ensuring the SOCO’s collected all pieces of evidence, securely packaged it,
labelled it, and described when and where they collected it.
Unknown 2: I was responsible for managing the cordon log, writing the date and time they
entered as well as time exited, their name and the reason for exit or entry. I was also responsible
for cordoning off the area to keep it secure and prevent contamination. In addition to all of that,
they were collecting evidence, packaging, and labelling it while taking photos of the scene and
evidence before it was packaged.
Unknown 3: They were responsible for sketching the evidence items and landscape/ details of
the crime scene (as well as taking measurements of each piece of evidence from the edge of the
cordon line. They were also responsible for photographing evidence, collecting evidence, and
taking notes of the crime scene. Furthermore, they were responsible for creating a bird's eye view
of the whole crime scene.
Unknown 4: They were responsible for placing evidence cards on the location of each evidence
we found and then took photographs of each evidence then packaged it while also labelling the
evidence, helped taking notes and helped in sketching the scene.
,Search methods:
Quadrant / Zone – The way this method is used is by splitting up the crime scene into smaller
sections and choosing another suitable search method to analyse the smaller zone. It is usually
used for scenes that are large or analyse a small area in an organised manner. After a period, the
investigators move to another section of the zone and analyse the same area another investigator
analysed; like a clock moving its hands around.
, Lane – An individual or group of investigators walk at the same pace in the same direction
(parallel to each other) to search for evidence. Typically used for finding larger objects in a large
area e.g., bodies in a forest.
Grid – Similar to a lane search but this covers double the area and allows different perspectives
for searching evidence on the same general path. Typically used for individuals or pairs/trios but
not large groups.
Spiral – Starting from the centre of a crime scene and spiralling outwards until the end of the
scene is reached, can be reversed, and start from the outside and work towards the centre.
Effective for single or pairs of investigators but not highly effective with groups.
