There are more than 800,000 police officers and detectives in America, according to the Bureau of Labor Statistics, and all these men and women employ the latest crime detection and investigation techniques.
Crime detection and investigation used to depend mostly on witnesses, hearsay or forced confessions. The first modern crime detection organization was Scotland Yard, established in the 19th century.
Crime detection begins with the discovery of a crime scene, and proceeds through the process of evidence collection, identification and analysis.
Crime scene investigation employs many forensic techniques, examining hairs or fibers, firearms, anatomy, bodily fluids and chemistry.
Surveillance is used when there is a high probability of a crime taking place at a specific place and time. Detectives are bound by all privacy laws, and must obtain a court order to intrude on privacy.
Interrogation is probably the oldest crime detection and investigation technique. Detectives interview all known victims or witnesses and interrogate suspects to further their investigation.