Unit 4 – Aim A – Explore procedures used to preserve, collect, and record forensic
evidence from a simulated crime scene.
Attending a crime scene: How Law enforcement should respond at a crime scene
I am a trainee Crime Scene Investigator and have been asked by my mentor to process a
local crime scene. I need to make sure I have all the correct equipment to limit
contamination and to collect potential forensic evidence. When arriving at the scene I need
to methodically search, preserve ad recover all potential evidence for analysis.
Restriction of access
When arriving at a crime scene the most important thing to do is secure the scene while
avoiding as little contamination of evidence as possible. The officers who first arrive will
assess the scene and treat it as a crime scene. The responding officers should be observant
and look out for any people, vehicles, events, or evidence near or at the scene.
The initial responding officer should: note the dispatch information, for example the
location, the time, the date, and the address. They should be aware of any people or
vehicles leaving the crime scene and approach the scene cautiously while making
observations. There are safety procedures that need to be followed and carried out. Any
physical threats need to be controlled to ensure the officers and individuals at the scene are
safe.
After controlling any hazardous situations, the responding officers next responsibility is to
ensure that any medical attention is supplied to any injured people while trying to minimize
any contamination at the scene. The responding officer should assess the victim for any
signs of life and ensure any medical attention is provided. They need to guide the medical
personnel to the victim to minimize contamination and point out any physical evidence to
them. The officer needs to make sure the medical personnel doesn’t clean up any mess as
this could be critical evidence. As well as this any statements or comments made by victims,
witnesses, or suspects at the scene need to be documented. If the victim is still alive and
transported to a medical facility an officer should be sent with them to document any
comments made and to preserve evidence. As well as this an officer is also needed to
protect the victim as the offender could return.
At the crime scene the responding officer needs to control, identify, and remove any people
at the scene to limit the number of people who enters or leaves the scene. As the
movement of people can leave or pick up and evidence which could be crucial during the
investigation. The responding officers should control all individuals at the scene, including
suspects, witnesses, and victims. Any bystanders could be witnesses so they should be
,questioned and not removed from the scene. Any family members or friends of the victim
who are there should be controlled while showing compassion.
There are boundaries which need to be controlled to protect and secure the crime scene.
This is determined by the location and the type of crime. Crime scenes can be internal, for
example in a house, vehicle, or building, or it can be external where it is outdoors, for
example a lake, park, or forest. Within these categories it can either be a public or private
place. The responding officer should establish boundaries of the scene depending on the
location of the crime, starting at the crucial point, and expanding outwards, including where
the crime occurred. At the crime scene no one should smoke, use a phone, eat, or drink or
move any weapons, unless necessary for the safety of the person at the scene. Any point or
paths of exit and entry of any suspects or witnesses need to be marked as well as any places
where the victim and evidence may have been moved. Physical barriers need to be set up,
for example rope, police tape, or cones. Another physical barrier the police can do to restrict
access is place police cars and vehicles near the area so people can’t get through.
After this the control of the crime scene will be handed over to the investigators in charge.
They will be briefed to help establish any further investigative responsibilities. The
responding officer will provide a detailed description of the crime scene and everything they
know so far to the investigator. Any activities and observations must be documented as
soon as possible to preserve information. The responding officer at the crime scene must
produce clear and detailed documented information about their observations and actions.
This is vital in providing information to help with the investigation.
Restricting access to a crime scene is important during an investigation as it preserves the
evidence at the scene, so no contamination or damage can take place. By preserving the
crime scene and making sure no unauthorised personnel is allowed through, lowers the
chance of this happening. Only authorised personnel are allowed access to near and on the
actual crime scene. Authorised personnel includes the first attending officer (FAO), the
Crime Scene Investigator (CSI), crime scene manager, fire and rescue officers, police officers
and forensic scientists. Any unauthorised personnel entering a scene or an authorised
person not wearing the right protective clothing, can either leave their own DNA as
evidence or damage and contaminate the evidence already there, this can hinder a case.
With any contamination or damage to evidence the whole investigation and case can be
thrown out and ruined, meaning justice won’t be served. Keeping any public, media, and
onlookers as far away as possible from the crime scene is vital as evidence is needed to
prosecute a case and any damage, destruction, or contamination to it can affect the whole
investigation. Another way to restrict access or to keep the crime scene away from any
onlookers and out of view is using forensic tents. These tents ensure the victim and scene
are out of the view of the public, giving privacy to the investigators and forensic scientists.
The advantages of restricting access and only letting authorised personnel in helps with the
continuity and chain of evidence as it is recorded exactly who and when a person enters the
scene. This avoids any contamination or damage to evidence. Anyone who enters the crime
scene has to sign in and out and log their title and reasoning for entering, including their
name and time of entry. This helps with the continuity and chain of evidence as the
evidence goes from crime scene to court room. Restrictions like police tape, cones and
, barriers are put up to stop unauthorised access, therefore stopping any contamination.
Crime scenes have an outer border/perimeter which keeps unauthorised personnel away
from the scene. The inner perimeter allows just officers and official personnel in, and the
final perimeter is the actual crime scene that is restricted strictly. In an investigation it is
important to keep the number of people entering a scene limited as too many people can
get confusing and contaminate or damage the scene. By not restricting access to a crime
scene results in many problems arising which can alter the preservation, collection and
recording of forensic evidence. Not restricting access to a scene allows unauthorised
personnel to enter and trample all over potential forensic evidence while damaging and
contaminating it. This means the evidence is not preserved or recorded and can’t be
collected or used in court as it is damaged and contaminated, seen as unreliable, this is why
restriction of access is vital.
The continuity, chain of evidence and appropriate documentation is very important in
forensic investigation as if done wrong it could jeopardise a whole case and justice won’t be
served. If the chain of evidence is not recorded properly the evidence is considered
unreliable and may not be allowed to be used in court meaning the defence and
prosecution have no evidence to work with and a sentencing might be harder to get. The
reason for the evidence being disallowed in a court of law if the chain of evidence is
incorrect is because there needs to be a clear path from crime scene to court room showing
exactly where the evidence was found, where it went, who handled it, who transported it
and who examined it all the way up to who uses it in court. Recording the times, dates,
names of everyone who handles it ensures that the evidence is reliable.
Observation and recording, identifying, and targeting evidence.
When first arriving at a crime scene the investigators who collect evidence need to gather as
much information as they can about the scene before starting any examination of the scene.
A slow and planned approach is taken. The information gathered helps to prevent
destruction and contamination of evidence for example footprints or trace evidence. Once
the information is gathered a plan is made about how to approach the scene. Crime scene
notes and timing should be kept along the whole investigation. The inspection of the scene
will begin with a walk through of the area in all areas the crime took place. Here they will
find physical evidence. The evidence should be preserved collected and documented. Once
the evidence is recognised to seize it involves either using tape, tweezers and cotton tips
and the right packaging.
The observation and recording, identifying, and targeting of evidence at a crime scene is
very important as it lets the investigator gather the information needed to figure out what
happened and how. By taking photos, writing crime scene notes, and drawing sketches of
the crime scene allows the investigator to create a picture in their mind of the events that
took place. Observation and recording also allows the investigators to know where the
pieces of evidence are and possibly how they got there and allows them to create a plan of
the right way to go about collecting the evidence without contaminating or damaging it.
Noting the location of the evidence and creating a plan on how the scene will be examined
