Crime Scene Documentation. The first thing you do after securing a crime scene is document it. Always take pictures. They are the best record available. Describe the scene, its over all conditions.
Check dates on mail and newspapers.
Diagram the crime scene. Photos are good to show where an object is in relation to another object, but measurements tell exactly how far. Chain of Custody. Chain of Custody is of paramount importance to any investigation. It is the unbroken sequence of events that is caused by an item of evidence from the time it is found at the crime scene to the time it appears in court.