AC1.3 Explain how three different types of evidence is processed
Physical evidence can be explained through Locard’s exchange principle, which states that
every time someone enters an environment, something is added to and removed from it and
that every contact leaves a trace. There are different types of physical evidence including
bodily fluids, impression evidence, fingerprints and trace evidence. Scene of crime officers
(SOCOs) will always try to collect physical evidence at every crime scene. In order to not
contaminate the crime scene themselves, they must wear protective clothing such as the
‘bunny suit’. An outdoor crime scene is the most vulnerable to contamination as any
individuals with access to a crime scene can potentially alter, destroy or contaminate
evidence and weather conditions can also damage evidence at the crime scene. Officers
must corden off the crime scene and collect evidence swiftly to help prevent this. Each piece
of evidence at the crime scene is labelled with a number and a photograph of the whole
crime scene, as well as closer pictures of each evidence, must be taken before the SOCOS
actually enter the scene.
Shoeprints is an example of impression evidence. Before it is collected, photos should be
taken of the crime scene using a tripod, ruler and level and then casts can be made of
impressions left at the scene. Once the cast has hardened, it can be packaged in paper for
protection and placed in a secured container to be transferred and submitted to the lab. If it
is not possible to take the entire object with the print on it then a lifting technique can be
used. It is analysed in the lab by comparing the shoe mark with shoe prints or shoe
impressions from known samples and the shoe prints can be stored on databases that can
be later used for comparisons. The personnel involved would be SOCOs who collect the shoe
print and forensic scientists who analyse the shoe print. In 2017, police were able to catch
Odin Lloyd’s killer, Aaron Hernandez, who shot him in an industrial park, by matching the
shoe print found at the crime scene to one made with the same type of shoe that
Hernandez was seen wearing the same night in CCTV footage.
Another type of physical evidence is fingerprints. To collect fingerprints, the latent prints are
made visible by dusting them with magnesium powder or shining a UV light. Photos will be
taken and afterwards, the prints may be lifted with an adhesive strip and placed on an
acetate sheet. It is secured in an evidence bag to be transferred to the laboratory. It should
be placed in a container, sealed and labelled when stored in a secure evidence locker until
transferred. Fingerprint experts will analyse the fingerprints by looking for unique features
that will help compare them against those stored in databases to try and find a match. The
SOCOs collect the evidence and then it will be analysed by a forensic scientist which
specialises in fingerprints. In the Amanda Knox and Meredith Kercher (victim) case, the
Rome Forensic police were able to match fingerprints found in Kercher’s bedroom to Rudy
Guede. Guede was then arrested the next day in Germany and he was charged with the
murder.
Physical evidence can be explained through Locard’s exchange principle, which states that
every time someone enters an environment, something is added to and removed from it and
that every contact leaves a trace. There are different types of physical evidence including
bodily fluids, impression evidence, fingerprints and trace evidence. Scene of crime officers
(SOCOs) will always try to collect physical evidence at every crime scene. In order to not
contaminate the crime scene themselves, they must wear protective clothing such as the
‘bunny suit’. An outdoor crime scene is the most vulnerable to contamination as any
individuals with access to a crime scene can potentially alter, destroy or contaminate
evidence and weather conditions can also damage evidence at the crime scene. Officers
must corden off the crime scene and collect evidence swiftly to help prevent this. Each piece
of evidence at the crime scene is labelled with a number and a photograph of the whole
crime scene, as well as closer pictures of each evidence, must be taken before the SOCOS
actually enter the scene.
Shoeprints is an example of impression evidence. Before it is collected, photos should be
taken of the crime scene using a tripod, ruler and level and then casts can be made of
impressions left at the scene. Once the cast has hardened, it can be packaged in paper for
protection and placed in a secured container to be transferred and submitted to the lab. If it
is not possible to take the entire object with the print on it then a lifting technique can be
used. It is analysed in the lab by comparing the shoe mark with shoe prints or shoe
impressions from known samples and the shoe prints can be stored on databases that can
be later used for comparisons. The personnel involved would be SOCOs who collect the shoe
print and forensic scientists who analyse the shoe print. In 2017, police were able to catch
Odin Lloyd’s killer, Aaron Hernandez, who shot him in an industrial park, by matching the
shoe print found at the crime scene to one made with the same type of shoe that
Hernandez was seen wearing the same night in CCTV footage.
Another type of physical evidence is fingerprints. To collect fingerprints, the latent prints are
made visible by dusting them with magnesium powder or shining a UV light. Photos will be
taken and afterwards, the prints may be lifted with an adhesive strip and placed on an
acetate sheet. It is secured in an evidence bag to be transferred to the laboratory. It should
be placed in a container, sealed and labelled when stored in a secure evidence locker until
transferred. Fingerprint experts will analyse the fingerprints by looking for unique features
that will help compare them against those stored in databases to try and find a match. The
SOCOs collect the evidence and then it will be analysed by a forensic scientist which
specialises in fingerprints. In the Amanda Knox and Meredith Kercher (victim) case, the
Rome Forensic police were able to match fingerprints found in Kercher’s bedroom to Rudy
Guede. Guede was then arrested the next day in Germany and he was charged with the
murder.
