Unit 23: Forensic Evidence, Collection and Analysis
A: Understand how to gather forensic evidence, the integrity to forensic investigation and the importance of health and safety
Gathering and preserving forensic evidence
This report will outline how a crime scene is processed, how forensic evidence is gathered and preserved and the
importance of health and safety in forensic investigations.
Roles of crime scene personnel
The crime scene personnel are a group of people that work in cooperation to examine a crime scene, gather physical
evidence and send the evidence to a laboratory for further analysis. They consist of the following roles:
A first attending officer (FAO), who is usually the first one to attend a crime scene [Annets, F. 2018]. This is usually a
police officer [Annets, F. 2018]. The FAO assesses the crime scene and establishes whether assistance is necessary,
such as paramedic staff and/or fire and rescue service officers [Annets, F. 2018]. They search for and arrest any
suspects if they are still present at the crime scene, establish if there are any injuries or witnesses and may be
responsible for preserving certain pieces of forensic evidence from weathering [Annets, F. 2018].
Scene of crime officers (SOCOs), also known as crime scene investigators (CSIs), who are needed to collect and
preserve evidence at a crime scene. They preserve evidence to ensure that it can be used in a court of law.
A crime scene manager (CSM), who lead a team of SOCOs in their evidence collection. This is important so that
investigation strategies can be planned accordingly. CSMs also ensure that the authorised personnel are following
health and safety legislations, such as by wearing PPE throughout their investigation.
Paramedic staff, who attend a medical emergency if they are any individuals at the crime scene who are injured. This
is important so that they can assess whether the patient needs further treatment at a hospital.
Fire and rescue service officers, who are needed to extinguish a fire and to rescue anyone trapped in fire or vehicles
[National Fire Chiefs Council, n.d.]. They also preserve evidence at the scene, such as noting down physical evidence
[National Fire Chiefs Council, n.d.]. This is then kept in a secure storage area; service procedures are needed for its
collection and handling [National Fire Chiefs Council, n.d.].
Structure of scientific support units (SSU)
A scientific support unit is a group of professionals who provide scientific knowledge and assistance to law
enforcement agencies during criminal investigations. The structures of SSUs vary between regional forces but they
usually consist of the following:
CSIs attend crime scenes and recover forensic evidence (such as fingerprints, DNA and footwear impressions). They
also take photos at crime scenes- some forces have specialist forensic photographers [Annets, F. 2018]. CSIs are
important in crime scene investigations because evidence collection carried out by them will help in detecting and
prosecuting suspects [Joining the Police, n.d.].
Crime scene coordinators oversee complex crime scenes [Annets, F. 2018]. Crime scene coordinators are critical for
ensuring the effective coordination, decision making and management of a team of crime scene investigators [West
Midlands Police - Recruitment Team, n.d.].
Forensic scientists (these may include forensic pathologists, archaeologists or anthropologists. They are usually
needed if there is potential evidence that relates to a certain specialist area. Forensic scientists are a crucial part of
the criminal justice system because they examine and analyse evidence that can assist in the prosecution of
perpetrators and remove suspicion from an innocent person [The United States Department of Justice, 2018].
, Unit 23: Forensic Evidence, Collection and Analysis
A: Understand how to gather forensic evidence, the integrity to forensic investigation and the importance of health and safety
SSUs play an important role in forensic science because they can use advanced scientific technology to improve their
interpretations of physical evidence, which can in turn lead to the discovery of new evidence. They also provide
reliable evidence that can be presented in court.
Comparing the roles of members involved in a crime scene
The crime scene personnel and the SSUs are both major groups involved in crime scene investigations. However, the
roles of each group differ significantly. In an SSU, the evidence is sent to a forensic scientist for further examination.
When examining evidence, they must wear full PPE in case they are dealing with evidence that is contaminated with
certain dangerous substances. This meets the Personal Protective Equipment at Work Regulations (1992), which
states that employees should be given instructions on its use and that they must use PPE correctly to prevent the
chances of contamination [Johnson, E. 2020].
Incident commanders are part of the crime scene personnel and they use cordons to keep the public away from the
crime scene [NFCC, n.d.]. This is done so that the evidence from the crime scene remains in its original location,
allowing police to look for, collect and make a record on where each piece of evidence was located at the time of the
search. This increases the integrity of the evidence collected. Using police cordons to block off an incident from the
public meets Section 7 of the Health and Safety at Work Act (1974), which outlines that employees must consider
the health and safety of the general public who could be affected by being exposed to the incident [Worknest,
2019]. It also meets the Management of Health and Safety at Work Regulations (1999). Members of the crime scene
personnel (such as the first attending officer and emergency services) are responsible for being at the crime scene to
ensure that any casualties are dealt with such as by escorting them to a hospital for further medical treatment. They
are the first groups of individuals present at a crime scene. SSUs are then involved with the procedures that are
carried out after the initial observations carried out by the crime scene personnel members. They are responsible
for an observation of the scene, documentation of evidence and collection of evidence.
Gathering forensic evidence
1. Restriction of access to the scene
When the CSI team arrives on the scene, it is critical that a number of security and safety concerns are addressed
before the scene or evidence can be processed. Access must be restricted to prevent evidence from being destroyed
or contaminated. As a result, only authorised personnel are permitted to enter the crime scene using a common
approach path (CAP). A common approach path is used to establish the entrance and exit points of a crime scene.
This must be created in a way that will prevent disturbance or contamination of the crime scene, in order to
preserve the evidence and its location. An example of how a CAP can be established is by using numbered
identification cards and placing them at certain locations of a crime scene to mark each evidence item.
Barrier tape, vehicles, and guards are used to create a police cordon that encloses the crime scene. A log is also kept
to track who enters, their role, time of entry and time of exit. This is important to ensure that the continuity of
evidence is maintained throughout [Annets, F. 2018].
Impact of not restricting access to the crime scene
If access is not restricted and cordoned off (eg. by using police cordon tape), then anyone who enters the crime may
potentially contaminate or destroy evidence by accident. Therefore, it is crucial to restrict access to the public so
that the crime scene can be preserved and that the crime scene can be processed whilst in its original state [Annets,
F. 2018].
