The police procedural, police show, or police crime drama, is a subgenre of procedural drama and detective fiction that emphasizes the investigative procedure of police officers, police detectives, or law enforcement agencies as the protagonists, as contrasted with other genres that focus on non-police investigators such as private investigators.
As its name implies, the defining element of a police procedural is the attempt to accurately depict law enforcement and their procedures, including such police-related topics as forensic science, autopsies, gathering evidence, search warrants, interrogation and adherence to legal restrictions and procedures.
While many police procedurals conceal the criminal's identity until the crime is solved in the narrative climax (the so-called whodunit), others reveal the perpetrator's identity to the audience early in the narrative, making it an inverted detective story.
The police procedural genre has faced criticism for its inaccurate depictions of policing and crime, depictions of racism and sexism, and allegations that the genre is "copaganda", or promotes a one-sided depiction of police as the "good guys".
The roots of the police procedural have been traced to at least the mid-1880s. Wilkie Collins's novel The Moonstone (1868), a tale of a Scotland Yard detective investigating the theft of a valuable diamond, has been described as perhaps the earliest clear example of the genre.
As detective fiction rose to worldwide popularity in the late 19th century and early 20th century, many of the pioneering and most popular characters, at least in the English-speaking world, were private investigators or amateurs. See C. Auguste Dupin, Sherlock Holmes, Sam Spade, Miss Marple and others. Hercule Poirot was described as a veteran of the Belgian police, but as a protagonist he worked independently. Only after World War II would police procedural fiction rival the popularity of PIs or amateur sleuths.
Lawrence Treat's 1945 novel V as in Victim is often cited as the first police procedural, by Anthony Boucher (mystery critic for the New York Times Book Review) among others.