The model answer I used for the Unit 3 Controlled Assessment in the A.C.1.2 section that achieved me an A* (UMS 100).
Expertly written write up for assessing the usefulness of investigate techniques in criminal investigations.
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A.C.1.2 - Assess the usefulness of investigative techniques in criminal investigations
Forensic - DNA
Forensic evidence refers to scientific techniques and tests that are used in assisting
in investigations, and DNA carries genetic information which is unique to each individual and
found constantly at crime scene due to DNA evidence including minor cells such as hair
follicles, skin flakes and bodily fluids such as semen and blood.
DNA is useful in a criminal investigation due to everyone's DNA being different,
therefore a high reliability in finding the correct offender based on a DNA match. It is useful
in old criminal investigations where DNA was stored in order to re-test it after a longer period
of time, providing a chance to find conclusive results. Due to DNA being everywhere, it
allows a chance to identify a victim when other methods of identification fail to do so as DNA
does not change, yet appearance can. DNA profiling has become the most important part of
developing an investigation as rapid analysis of DNA small samples has made it possible to
continue the investigation with little time wasted.
On the other hand, DNA evidence can only be matched when a suspect is already on
the DNA national database, therefore making it harder to convict a suspect who has never
committed a crime before. However, familial DNA may be able to perpetrate a suspect. For
example, Colette Aram’s case, who was murdered in 1983 before DNA testing was
established, but police were able to develop a DNA sample from the scene and a local pub
where the suspected murderer was seen in order to test later. DNA from the suspect’s son
was able to prove a DNA match, in which Paul Hitchinson was found guilty and jailed for 26
years. This proves DNA was useful as it was able to convict the suspect through alternative
ways, which are considered a limitation of the technique.
Another weakness of DNA is that cross-contamination is possible which may lead to
an innocent person being wrongfully convicted. DNA testing can also be expensive, each
test costing around £20, which can be wasteful if the DNA is contaminated or not stored
correctly. In 2005, David Butler was acquitted for the murder of Anne Marie Foy, a sex
worker. A discarded cigarette but and skin flakes under her fingernails were presented as
evidence, which he was found guilty of. It was revealed David had a skin condition where his
skin flakes. DNA was not a useful technique as it allowed a miscarriage of justice to occur.
People became concerned with their civil liberties about DNA being kept from suspects who
were not convicted, which led to a law change in 2012.
DNA is most useful at a crime scene due to it being the primary source of evidence
for a sample, as well as a laboratory for it to be tested and analysed to get a result. It can
also be useful in the police station for mouth swabs to be taken for potential suspects,
making it easier to analyse or test a match against them again if a future offence were to
happen. DNA would not be useful on the street as it can be contaminated and not contained
properly. DNA is most useful in violent crimes and property crime due to DNA such as blood,
semen, skin flakes being able to test, but not useful in E-crime as there is no traceable
physical evidence to test.
This shows that overall, DNA is very important in a criminal investigation as it can be
a non-negotiable, solid piece of evidence in court to convict the offender if DNA is left at the
scene of the crime and analysed properly.
Surveillance - CCTV
Surveillance is a way of monitoring someone’s actions, for example, CCTV which is
used in buildings to track who enters and exits and at what time. Police use CCTV in
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