Unit 23: Forensic evidence, collection and
analysis
Name: Aishah’ Sofia Dirir Mahmoud
Teacher: Leah Carson
Assignment title: Gathering and preserving forensic evidence
Learning aim A: Understand how to gather forensic evidence, the integrity to forensic investigation
and the importance of health and safety
Submission: Resubmission
Date: 11/06/2025
, Gathering and preserving forensic evidence
The proper collection and analysis of evidence after incidents and crimes is important to reveal
the truth and identify perpetrators while backing up legal procedure. Evidence provides critical
details about the incident sequence and responsible parties which leads to justice. The process
of gathering and preserving evidence needs attention to potential evidence contamination and
tampering as well as improper evidence handling. Serious problems with investigation reliability
can result from these issues because they may cause wrongful convictions and free criminals
from punishment.
Procedure 1: Restriction of access
The first step for scene of crime officers (SOCO) or crime scene investigators (CSI) at a crime
scene involves handling security and safety matters before starting evidence processing. The
scene requires restricted access because any unauthorised entry might result in evidence
destruction or contamination. The crime scene entry is restricted to authorised personnel who
have to use a designated common approach path (CAP1). Authorised personnel need to follow
strict procedures to maintain the integrity of all evidence collected. Within a crime scene,
various authorised personnel have their unique responsibilities and roles to gather, preserve
and examine evidence correctly. The following covers the roles and responsibilities of
authorised personnel present at a crime scene.
The first attending officer (FOA) is usually the first person to arrive at the scene of the crime.
Their first job is to evaluate the situation, save lives and protect the scene by setting up a secure
cordon to prevent contamination. The FAO has to be careful not to compromise the need to
save lives with the need to protect potential forensic evidence since the integrity of the crime
scene is important for a successful investigation. They may also arrest any suspects still present,
locate witnesses and take immediate actions to protect fragile evidence, such as covering a
footprint to prevent it from being damaged by weather conditions.2
The scene of crime officer (SOCO) or the crime scene investigator (CSI) is responsible for
gathering and documenting physical evidence. Their role is to photograph the scene, collect
forensic evidence such as fingerprints, blood, and fibres, and tag all the items accordingly and in
writing to ensure the continuity of evidence. All these are necessary to prevent the evidence
from being unreliable and its integrity is not questioned during legal proceedings.
The crime scene manager is responsible for the entire investigation. They organise all forensic
staff (SOCO) activity to ensure that the investigation is systematic and according to the
1
Annets, Frances, et al. BTEC Level 3 Nationals Applied Science Student Book 2, Pearson
Education, Limited, 2017.
2
Annets, Frances, et al. BTEC Level 3 Nationals Applied Science Student Book 2, Pearson
Education, Limited, 2017.
analysis
Name: Aishah’ Sofia Dirir Mahmoud
Teacher: Leah Carson
Assignment title: Gathering and preserving forensic evidence
Learning aim A: Understand how to gather forensic evidence, the integrity to forensic investigation
and the importance of health and safety
Submission: Resubmission
Date: 11/06/2025
, Gathering and preserving forensic evidence
The proper collection and analysis of evidence after incidents and crimes is important to reveal
the truth and identify perpetrators while backing up legal procedure. Evidence provides critical
details about the incident sequence and responsible parties which leads to justice. The process
of gathering and preserving evidence needs attention to potential evidence contamination and
tampering as well as improper evidence handling. Serious problems with investigation reliability
can result from these issues because they may cause wrongful convictions and free criminals
from punishment.
Procedure 1: Restriction of access
The first step for scene of crime officers (SOCO) or crime scene investigators (CSI) at a crime
scene involves handling security and safety matters before starting evidence processing. The
scene requires restricted access because any unauthorised entry might result in evidence
destruction or contamination. The crime scene entry is restricted to authorised personnel who
have to use a designated common approach path (CAP1). Authorised personnel need to follow
strict procedures to maintain the integrity of all evidence collected. Within a crime scene,
various authorised personnel have their unique responsibilities and roles to gather, preserve
and examine evidence correctly. The following covers the roles and responsibilities of
authorised personnel present at a crime scene.
The first attending officer (FOA) is usually the first person to arrive at the scene of the crime.
Their first job is to evaluate the situation, save lives and protect the scene by setting up a secure
cordon to prevent contamination. The FAO has to be careful not to compromise the need to
save lives with the need to protect potential forensic evidence since the integrity of the crime
scene is important for a successful investigation. They may also arrest any suspects still present,
locate witnesses and take immediate actions to protect fragile evidence, such as covering a
footprint to prevent it from being damaged by weather conditions.2
The scene of crime officer (SOCO) or the crime scene investigator (CSI) is responsible for
gathering and documenting physical evidence. Their role is to photograph the scene, collect
forensic evidence such as fingerprints, blood, and fibres, and tag all the items accordingly and in
writing to ensure the continuity of evidence. All these are necessary to prevent the evidence
from being unreliable and its integrity is not questioned during legal proceedings.
The crime scene manager is responsible for the entire investigation. They organise all forensic
staff (SOCO) activity to ensure that the investigation is systematic and according to the
1
Annets, Frances, et al. BTEC Level 3 Nationals Applied Science Student Book 2, Pearson
Education, Limited, 2017.
2
Annets, Frances, et al. BTEC Level 3 Nationals Applied Science Student Book 2, Pearson
Education, Limited, 2017.
