Unit 23 - Forensic Evidence, Collection and Analysis
Institution
PEARSON (PEARSON)
I did get a distinction however PLEASE read through your assignment brief as all schools ask for different requirements, so somethings will be different (my advise would be to use this as a guide :) ). This includes a description of all roles within a investigation, types of evidence, types of dna ...
unit 23a gathering and preserving forensic evidence
gathering and preserving forensic evidence
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BTEC
PEARSON (PEARSON)
Applied Science 2016 NQF
Unit 23 - Forensic Evidence, Collection and Analysis
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Unit 23A - Gathering and preserving Forensic Evidence
Aim
You are a newly appointed Level 3 Apprentice Forensic Technician, working for a company called ForSci Ltd.
The company works with police forces in the UK and internationally, and with government and private
organisations throughout the world. Your Head of Department has devised a number of tasks for you to
complete as part of your induction programme. You will be using the evidence you generate from these tasks
to demonstrate to your Supervisor that you have sufficient knowledge and understanding of how a scene of the
crime is processed to become an active member of a Scientific Support Unit.
Introduction
Forensic science is a part of the fascinating element of the criminal justice system. Providing help to prove
cases that seem out of reach, through the analysis of the physical evidence found. In day to day terms, it is the
application of all science. This type of application can help investigators understand types of blood spatter
pattern, physics, learning the composition and source of evidence such as drugs and trace materials, which
would be chemistry, or determining the identity of an unknown suspect, biology. Meaning, the role of forensic
science in the criminal justice system, as well as the legal system, is extremely critical for cases.
Documentation of evidence must be recorded in order to keep track of it, usually, before the investigators
begin examining the crime scene, they must gather as much information as possible about the scene. A slow
and calculated approach is taken when dealing with crime scenes. Information is always gathered before to
prevent the destruction of valuable or fragile evidence such as trace evidence of shoe prints etc. When these
vital types of sensitive information are found, a plan is formulated as to how the forensics team should analyse
the scene of the crime (notes and relevant times should be kept on every aspect of the crime investigation)[1].
The trail area of the crime (the marked area of the physical evidence) which all apparent actions associated
with the crime that took place. The trail is usually marked by the presence of physical evidence. This may
include the point of entry, the location of the crime, areas where a suspect may have cleaned up, and the point
of exit. In some cases, a walkthrough may become secondary if potential evidence is in danger of being
destroyed. In that case, this evidence should be preserved, or documented and collected as quickly as
possible. The reason for the “walk through'' is to make note of the location of potential evidence, to mentally
outline how the scene will be examined. The walkthrough begins as close to the point of entry as possible. The
first place the investigators should examine is the ground on which they are about to tread. If any evidence is
observed, then a marker should be placed at the location as a warning to others not to step on the item of
interest[1].
A common and good technique to use indoors, on harder surfaces is the “oblique lighting technique”, which is
known as side lighting. In most cases, the only tool needed is a torch with a powerful concentrated beam of
light. Those investigating should ensure that the room has been darkened as much as possible. If in a case a
suspect has potentially touched a light switch that needs to be turned off, it must be ensured that it has been
dusted for fingerprints before proceeding. Any shades or curtains should not be closed until general
photographs have been taken beforehand. During this particular technique, the torch must be held about an
inch from the floor. This strong beam is then put at such an angle that it just barely sweeps over the floor
surface, almost parallel to the surface[2]. The light is scanned back and forth, and any evidence, such as trace
evidence and shop prints, will begin to appear dramatically. Usually, under normal lighting, this type of
evidence may be extremely difficult to identify or even invisible. As this walkthrough processes, investigators
must make sure that their hands are occupied, to prevent other unwanted fingerprints from being created at
the scene. It can be avoided by carrying notebooks, pens, torches etc. Finally, during this walkthrough, they
need to examine whatever may be above their heads, this could be ceilings, even tree branches), these areas
may compile or very valuable information such as blood splatters and bullet holes. Once completed, the scene
is usually documented with a camera, photographs or sketches even.
Documenting a crime scene
Video Recording
, When available, a video camcorder or camera is one of the first steps when it comes to documenting a crime
scene. Tapes and footage can provide a perspective on the scene layout which cannot be easily viewed
through photographs and sketches. Usually much more natural viewing dynamic to allow people to readily
view especially when demonstrating the crime scene and how the evidence relates to the crime. The video
camera should also have the correct date and time on the camera as not to compromise the footage credibility.
A title for each film should be added as well as smooth filming for easier viewing. The condition of the crime
scene should be unaltered, except marked areas by investigators and any lights that may be turned on during
the walkthrough[2]. Any alterations can be noted on the audio portion of the tape. Before recording, the
camera's filming range should be completely clear of other people and should be completely silent. This is to
avoid any disturbances and any statements made that do not correlate with the investigation.
There should be no cut scenes during filming, it should be one complete and consistent cut, as this can make
it appear as evidence has been tampered with. Filming should be slow and fluid to ensure nothing is missed
when filming, however, it can be easy to move a camera too fast when filming. This is a disadvantage of using
a video to document viewing details. Some usually have a tendency to pan past objects in a manner that does
not let the camera properly capture the object being viewed. Slow panning of an area once or twice is
necessary to avoid rewinding tape when viewing. Taping should only really be used to record a general
overview of the scene and surrounding area. It should continue throughout the crime scene using wide-angle,
close up, and even macro (extreme close up) shots to demonstrate the layout of the evidence and its
relevance to the crime scene. If videotaping in a residence, the camera can show how the pertinent rooms are
laid out in relation to each other and how they can be accessed. This is sometimes lost in photographs and
sketches. The tape should then be transferred to a high-quality master tape. The recording tabs should be
removed from the master tape after transferring the crime scene tape and the master should be stored in a
safe place. This is to prevent accidental erasure of the crime scene tape. Copies can then be made from the
master tape.
Still Photography
Photographs are an essential form of documentation when studying a crime scene, If a video camera is
available, then photographs will be the second step in recording the crime scene. If video is not available, then
still photography will be the first step. Still, photographs can demonstrate the same type of things that the
videotape does, but photographs from the crime scene can also be used in direct comparison situations. For
example, actual-size photographs can be used to compare fingerprint and shoe prints photographed at the
crime scene to known fingerprints or shoes from a suspect. This is the advantage of photographs over
videotape. Any flash unit used with the camera should be one that is not completely fixed on the camera.
Meaning that the camera must function at various angles and distances from the camera. This is to allow
lighting of certain areas to provide maximum contrast, place the flash in hard to reach areas, and reduce flash
washout which can render the item photographed invisible. A tripod, a level, and a small ruler should also be
available for photography. It may be of help to the investigation to have a polaroid camera handy for instant
photographs. For example, an instant photograph of a shoe print found at a crime scene can be provided to
investigators who are running a search warrant on a suspect's residence. The photo will tell them the type of
shoe for which they are searching.
The photography of the crime scene should begin with wide-angle photos of the crime scene and surrounding
areas. When shooting the general overall scene, the photos should show the layout of the crime scene and the
overall spatial relationships of the various pieces of evidence to each other. A good technique to use indoors is
to shoot from all four corners of a room to show its overall arrangement. The next set of photos should be
medium range to show the relationships of individual pieces of evidence to other pieces of evidence or
structures in the crime scene. Finally, close up photos should be taken of key pieces of evidence. A ruler
should be photographed with items where relative size is important or on items that need to have one-to-one
comparison photographs. The object should first be photographed as is, then photographed with the ruler. It is
important that when doing one-to-one photography that the ruler is on the same plane as the object being
photographed and the film plane is parallel to the ruler. This is why a level and a tripod are necessary. Notes
should also be taken as to what the investigator is photographing or wishes to demonstrate in each
photograph. This is to prevent the investigator from getting the picture back at a later date and trying to figure
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