Contamination is when a substance or item is brought into at a crime scene that was not present at the time of the incidence. The most common type of contamination is from forensic investigators that are investigating the crime scene that is not following correct procedures, from contaminated equipment, clothing or from contamination between samples collected. Therefore there are several procedures that must be followed to ensure that contamination is minimised when collecting, storing and examining the evidence from a crime scene and that it is managed both within the scene and outside of the scene.
The procedures that forensic investigators can follow to ensure prevention of the evidence being contaminated are; Investigators should wear barrier clothing also known as personal protective equipment (PPE), this will include items such as gloves, safety goggles, face masks or shoe covers. Wearing PPE will help reduce the likelihood of forensic investigators contaminating evidence for example through the shedding of hair or skin particles into the scene or to protect themselves from hazardous substances used at the crime scene. All PPE clothing that is worn must be recorded in a log. Providing entry tents to a scene could be a useful measure for separate designated areas for putting on and removing PPE clothing and the disposal of used clothing to avoid cross contamination between scenes. They might even find showering and changing clothes between investigations should allow strict cleaning and decontamination measures to be followed. Identifying clear paths ways that should be used or areas where particular items of protective clothing should be worn or other protection methods being used such as clean stepping plates used where protection of ground surfaces is necessary, is a control used to avoid cross contamination. Ensuring that the equipment used is well decontaminated before and after use, to avoid cross-contamination between individuals or different scenes or other evidence samples is also an important step to be followed.
Another procedure is that forensic investigators should ensure they are following Standard Operating Procedures (SOPs) as this improves the credibility of the investigation and evidence collected providing a more reliable case for the jury. The mishandling of evidence could destroy the evidence’s credibility to the investigation, therefore the forensic investigator must use the correct procedure to handle evidence, store and preserve evidence where needed. When approaching the scene of the crime the forensic investigator should as soon as possible secure the crime scene from entry from members of the public by using barricades or corroding off areas of the investigation for authorised users to access only. However, at this point, it is vital that the scene is not altered and its original state is maintained until all evidence is collected, documented or photographed. Providing a scene log of records of entry to the scene and the activities taken place inside will help control the measure.
A forensic scientist is a expert in studying crime investigations using their knowledge and skills to help solve cases under investigation by a court of law. There are several behaviours which would deem a forensic scientist to be reliable. The reasons are as follows.
A forensic scientist must have the ability to analyse information within a criminal investigation to a high level, as analysing is a key role of their job, to help solve complex problems. They use scientific practices and testing on evidence to provide the court of law with important information and findings on their cases. The ability to also be detailed and being able to break down information through critical thinking is vital to the conclusion of a investigation.
They must control the accuracy of their investigations to ensure their findings are reliable, such as retaining precise records and having controlled environments for examination of evidence. Forensic scientists are accountable for their findings and may need to provide their reports amongst the court. The ability to be ethical in their role is vital, as within their assessments they are expected the uphold the law. This involves constructing tests and written reports which are accurate and carefully written to ensure the documentation incorporates all mandatory information.
Forensic scientist must be well spoken so that they are able to expand on their findings in the court as expert witnesses. They must also be skilful writers so they can provide thorough reports of those findings. Communication skills is a key characteristic of a forensic scientist because part of their job is explaining their complex scientific data in a straightforward term that any person outside of their scientific field can understand and supporting that evidence aswell to prove its reliability.
Forensic scientists are experts in both criminal and civil cases. They excel in areas such as documentation analysis, fingerprinting, DNA evaluation and identification of firearms present at a crime scene. They are individuals which enjoy learning and exploring new areas to help develop their own knowledge and to help create new techniques. It this large capacity of knowledge that they obtain which helps them compare their observations and draw conclusions. This enables them to be called upon as expert witnesses in court due to their wide knowledge base and education within this profession.
Damilola Taylor was the victim of a vicious attack in November 2000. At the age of only 10 years old he was fatally stabbed in the leg with a broken glass which caused several blood vessels to collapse causing his death. This crime was committed by two young brothers who was eventually named Danny and Ricky Preddie, well known young offenders, aged only 12 and 13 at the time of the offence.
The forensic scientists played a particularly vital role in this investigation. It was their role to examine the evidence collected from the crime scene that could determine who committed this crime. It would also be their role to act upon as expert witnesses of this investigation and show this evidence in court. They would have taken over from the police at the initial crime scene and would have collected vital evidence from the scene that they thought would be necessary for further investigation to help solve this crime. This would have been evidence such as the broken glass found from Damilola’s injury, blood left on the crime scene or on Damiloa’s body, fingerprints on the broken bottle and Damilola’s items of clothing he was wearing. They also could have examined the clothing of the suspects had been wearing at the crime scene. However in this particular investigation evidence was overlooked by the forensic scientists due to human error which caused great difficulty in determining who would be prosecuted for this fatal attack towards young Damilola and which is what lead this case so long to locate the pivotal forensic evidence. In the first trial in 2002 not enough forensic evidence was produced in court for the four initial suspects to be charged, it was thought that Damilola’s injuries were caused by a fall onto a broken bottle and that he was not attacked at all. Two suspects where dismissed and two others where dropped from the investigation as where proven to have no involvement in this crime.
The investigation remained open after the first trial and it was requested upon by the court that the evidence from the scene would be re-examined. Forensic scientists used new DNA testing techniques to re-examine the clothing seized from the crime scene. It was through these techniques that scientists where able to identify Damilola’s blood on two of the initial suspects items of clothing. One spot was found on the white reebok trainer which belonged to a 17 year old boy, Daniel Freddie. Within this blood spot a piece of fibre from Damilolas trousers that he had been wearing when he was stabbed was found. This was an immediate link towards this young boy and the death of Damilola. The second blood spot was found on the cuff of a sweatshirt of a second initial suspect, the brother of Daniel Freddie, Richard Freddie. Other fibres from Damilola’s clothing was also discovered during the examination on the clothing of a third boys tracksuit bottoms.
It was clear that the forensic evidence involved in this investigation was a key involvement in bringing justice for Damilola Taylor’s death.