Explain what needs to be done at the crime scene so that the evidence that is collected will be admissible in court

Question

What will be an ideal response?

Answer 1

When evidence is collected at the crime scene two different things need to be kept in mind. First, each item that is found must be protected from contamination and/or destruction. To do this, the person in charge of collecting the evidence must be trained in how to collect various types of evidence and have an assortment of receptacles with him/her. The exact location where the item was found needs to be recorded. In order to avoid contamination, the number of people who have access to the scene must be limited. Those who are allowed to enter the scene must be constantly on guard so that they do not step on, or otherwise destroy, items with evidentiary value. The evidence tech also needs to know how to store a wide variety of evidence. For example, a blood-soaked piece of clothing must be dried before it is stored, while something that would indicate that the suspect had recently consumed alcohol or used gasoline needs to be stored in airtight containers so that the volatile liquid does not evaporate.
The second important thing that needs to be done is to preserve the chain of custody (also called chain of possession or continuity of possession). Records need to be kept that document the identity of each person who had access to the item, and what was done with each item, from the moment it came into the police custody until it is introduced into evidence at trial. Each person who has custody should sign for it when receiving it, and make sure to sign it over to the next recipient. This painstaking process is done so that no one will be able to say that the item was tampered with before it got to court. If a lab test changes the appearance of an item, this fact needs to be in the record as well.