Electronic evidence – new guidelines for police

The revised Good Practice Guide for Computer-based Electronic Evidence covers the physical recovery of evidence from computers, PDAs and mobiles, and also makes recommendations on the use of expert witnesses.

According to the Guide:

"Computer based electronic evidence is, by its very nature, fragile. It can be altered, damaged, or destroyed by improper handling or improper examination. For this reason, special precautions should be taken to document, collect, preserve and examine this type of evidence. Failure to do so may render it unusable or lead to an inaccurate conclusion."

There are four guiding principles to ensuring the integrity of computer-based electronic evidence:

• Nothing should be done that would change the data held;
• The data may be accessed at the scene – in exceptional circumstances only – by a competent person who is able to explain how and why the access was made;
• A record must be made of everything that is done to the data, capable of being verified by an independent third party; and
• The case officer is responsible for ensuring the law and the principles are kept to.

The guide also explains the choice and role of expert witnesses, who are also expected to follow the guidelines.