Trace Evidence

P.S.I. Investigations llc
Professional Service Integrity

P.S.I Investigations Blog

Check back often for up-to-date information about our latest investigations, resources and tools! 

Neil uncovered fraud and hidden assets during my recent divorce proceedings, finding over $450,000.00 in hidden assets and accounts. Neil is an honest accomplished investigator with an excellent reputation.

Whatcom County

Neil Harrison
Enter your email address below to receive updates when new blog posts are added!
Search All Blog Posts
Most Recent Posts
Blog Post Archive Categories
Trace Evidence
By: Neil Harrison ~ 3/18/2020

The key principle in Crime Scene investigation is the concept known as 'Locard's Exchange Principle'.

It states that whenever someone is present at the scene of a crime, something physical is either left behind and/or taken away.

This principle allows investigators to link suspects, victims and scenes/objects through 3 primary methods;

1. Associative Evidence - trace evidence directly linking a suspect to the scene/location of the crime

2. Reconstructive Evidence - helps determine the actions and events that took place at the scene/location

3. Control Evidence - scene samples used to circumstantially link a suspect to a scene usually at a later date

It is important to note that evidence that may be collected in order to identify and prosecute a suspect, is equally important in excluding potential suspects during an effective investigation.