PHYSICAL EVIDENCE
- Evidence plays a pivotal role in trials and investigations.
- However, how it is processed can affect the entire case, potentially leading to false accusations
or allowing a criminal to walk free.
- There are two types of evidence: physical and testimonial.
- Physical evidence consists of concreate articles which could include blood, seminal stains,
fingerprints, and biological materials.
- Whereas testimonial evidence allows people the opportunity to provide their own written or oral
statements on their take of the crime.
- This could be from eyewitnesses, victims, or defendants and in several cases
- expert witnesses.
- The process of collecting such evidence must ensure procedures are strictly adhered to.
- Physical evidence is collected, often by SOCOs which then gets transferred to a lab to get
analysed which is then stored.
- During the collection process it is possible that evidence may get contaminated.
- This happens when people don’t wear 2 pairs of sterile and fresh protective gloves or protective
clothing.
- Face coverings and protective gear such as shoe coverings and a scene suit, are often worn in
more serious crimes to prevent any form of cough, sneeze or breath particles transferring onto
the crime scene and to protect themselves from any hazardous substances.
- When collecting physical evidence, different equipment is used depending on the type of
evidence.
- When collecting blood that is still in liquid form a clean cotton cloth or gauze pad is used to take
samples of the blood; this should then be left to air dry at room temperature.
- To transfer the evidence without going bad, it should be kept refrigerated or frozen a
- quickly as possible and brought to a laboratory.
- This evidence may become inadmissible if there are delays in transfers that exceed the 48-hour
mark.
- When storing blood, it must be made sure that the physical evidence is dry and then again
refrigerated or frozen.
- However, at a scene where the blood is stained onto an item of clothing or material, it should be
covered in clean paper and then the article placed in a brown bag or box which is then sealed
and must be labelled.
- It is extremely important that the stains mustn’t try to be cleaned off the items.
- This evidence is then analysed in a laboratory to discover the blood type or uncover whose DNA
is present.
- This is useful in investigations as it provides more evidence in which comparisons can be made to
link the crime to who the victim is, and the perpetrator is by seeing who the blood belongs to.
- Two personnel are mainly involved when collecting evidence such as blood:
- a pathologist’s role in this process is to have a doctor’s opinion and investigate the cause of
death by studying the autopsy by doing an external examination of the body.
- SOCOs are the individuals who find and collect evidence and remove, if necessary, from the
crime scene.
- Forensic scientists test evidence such as semen to analyse and identify who’s DNA is found.
- A case in which SOCOs and the police force did not strictly adhere to procedures was the
Amanda Knox case.
- Amanda and her partner Raffaele Solicto were convicted of the murder of her flat mate,
Meredith Kercher, receiving a 25-year sentence.
- In 2011 they were released and then re-trialled again in 2013 in Italy.
- However, in 2015, the supreme court overturned their convictions.
- It was argued that the crime scene had been contaminated and was not sectioned off properly.