Criminal investigation is an applied science that involves the study of
facts that are then used to inform criminal trials. A complete criminal
investigation can include searching, interviews, interrogations, evidence
collection and preservation, and various methods of investigation. Modern-day
criminal investigations commonly employ many modern scientific techniques
known collectively as forensic science.
Criminal investigation is an ancient science that may have roots as far back
as c. 1700 BCE in the writings of the Code of Hammurabi. In the code, it is
suggested that both the accuser and the accused had the right to present
evidence they collected. In the modern era, criminals investigations are most
often done by government police forces.