Criminal Investigation in Practice - Procedures for Collection & Preservation of Evidence

When evidence is collected from a crime scene, it is essential that it is collected, packaged and labelled efficiently to preserve the item and keep all evidence intact.

"Bagging and Tagging" 

The collection and preservation of evidence depends on the type of evidence that is at a crime scene. There are three main categories of evidence:

Biological - Evidence from that comes from something living e.g. Blood, Bodily Fluids, Pollen etc;

Chemical - e.g. Drugs, Gunshot Residue, Accelerants, Paint etc

Physical - e.g. Weapons, Footwear Marks, Vehicles, CCTV etc

To collect these types of evidence, there is a procedure to follow where gloves are put on, instruments are used to collect the evidence depending on the evidence itself, for example, blood would be collected using a cotton swab and hair would be collected using tweezers. Then the evidence would be packaged according to the evidence for example, a weapon would be packaged in a box or tube and accelerants would be collected in a plastic container. Biological evidence such as blood and bodily fluids are not to be packaged in plastic bags as these can cause the fluid to sweat and evaporate leaving poor evidence for analysis. Bodies are collected by a coroner that takes the body to a forensic pathologist that can determine the cause of death; the body has to be packaged in such a way that and evidence on the body is not disturbed so a body tends to be covered with plastic sheeting that can then also be analysed for any evidence that may have been transferred off the body.

In the case of the Moors Murders, there was lots of different types of evidence found:

Found at 16 Wardle Brook Avenue:

• The Body of Edward Evans - this would have been packaged in a body bag to preserve evidence on the body and the body itself for a post-mortem examination.
• The Hatchet used to murder Edward Evans - would have been packaged in a box to prevent the hatchet from being damaged.
• Left Luggage Tickets found in Myra Hindley's Prayer Book - would have been packaged in a paper envelope to protect them from other fingerprints.
• Ian Brady's Notebook containing John Kilbride's name - this would have been put into a bag or box to keep the notebook dry and clean of any contamination.

Found at Manchester Central Station: 

• Suitcases containing pornographic images of Lesley Ann Downey - these would have been packaged in an envelope to prevent fingerprints from being left on them and to also prevent them from degrading and then being unable to be used as evidence.
• A Tape Recording of Lesley Ann Downey - packaged in a box to prevent contamination from other sources.
• Other various sadistic paraphernalia - packaged in a box to prevent contamination.

Found on the moors surrounding Manchester:

• The Bodies of Lesley Ann Downey, John Kilbride and Pauline Reade - these would all have been packaged into body bags to preserve the bodes for post-mortem examinations and to also collect any other evidence that might be found on the bodies.

From Securing the scene to presenting the evidence in court, there are many steps that need to be followed to preserve and protect evidence. The first step is to secure the scene by setting up a cordon and other protective equipment to preserve evidence e.g. a shelter to protect outdoor evidence in the rain. This would be carried out by the First Attending Officer who would also collect witness statements and arrest any potential suspects at the scene. The crime scene investigators would then arrive and conduct an initial scene assessment and note down details of the scene as well as taking photographs of the scene. They would then collect evidence that is relevant to the crime. This evidence would be packaged accordingly and given to the senior police officer at the scene to then be taken to the lab along with an evidence chain of custody log that records who has opened evidence and for what purpose. The evidence would then be taken to the lab for analysis to provide scientific proof of the crime occurring and who committed it. Once the evidence has been analysed, a case file is put together stating the facts and results from testing and analyzing the evidence. This is later used in court with the evidence sealed to show the court what has been collected and analysed by the forensic scientist. There are many people who have access to the evidence, hence why an evidence chain of custody log is used to be able to see who has accessed the evidence and to ensure that there is no contamination from outside sources.