The police procedural is a sub-genre of the mystery story which attempts to convincingly depict the activities of a police force as they investigate crimes. Unlike typical detective novels, which concentrate on one crime, police procedurals frequently show how police officers work to solve multiple crimes simultaneously. In contrast to the whodunit convention of having the criminal's identity concealed until the climax, in police procedurals, the perpetrator's identity is often known to the reader from the outset. Police procedurals depict a number of police-related topics such as forensics, autopsies, the gathering of evidence, the use of search warrants and interrogation.

Lawrence Treat's 1945 novel V as in Victim is often cited as the first police procedural. The genre moved to radio and then television with Dragnet in the late 1940s and early 1950s. In the 1980s, Hill Street Blues pioneered the depiction of the conflicts between the work and private lives of officers. In 1990s and 2000s, the Law & Order series depicts the two 'halves' of a criminal proceeding in the criminal justice system: the investigation of the crime by the police detectives and the subsequent prosecution of the criminals by the district attorney's office.