Police investigations establish the legal framework for bringing law enforcement to a crime scene, collecting evidence and capturing and prosecuting offenders. When properly conducted, they preserve the rule of law and due process and aid in delivering justice to victims.
When police investigate a reported incident they may interview witnesses, examine physical items such as fingerprints or blood samples and review electronic information like cell phone data and online searches. They must carefully document each piece of evidence and maintain an unbroken chain of custody so that it cannot be tampered with.
Investigations can be complicated and sometimes take time to build a solid case for the prosecution. Detectives should work every line of inquiry to gather material that points both towards and away from a suspect, according to the Home Office (2020).
Investigators must also be careful not to contaminate the crime scene; contamination can destroy vital evidence or ruin forensic techniques. They must always follow the U.S Constitution’s rules on search and seizure; this means they can only look at private property with a warrant or probable cause.
If you’re a victim or witness of crime, you should be given the leaflet, ‘Information for victims of crime’, by an officer at the police station, and told when you will be interviewed. It’s important that you let the investigating officer know if an accessibility accommodation is needed for your interview, or you do not understand something. You can also ask for an interpreter to help you.