According to IMDb it was filmed in 1981 and released in 1983 in Italy and 1984 in United States. It is Lydon's only starring role in film to date.
Lieutenant Fred O'Connor (Keitel) and his partner, police officer Bob Carvo (Mann), are a pair of corrupt cops who have spent their illegal earnings on an uptown New York City flat. A friction starts between them, as Carvo feels guilty about their scams and wants to abandon their association. Meanwhile, the police force of the city is trying to catch a serial killer who has chosen corrupt policemen as targets. The man, who has been nicknamed "Cop Killer" by the press, has apparently been watching O'Connor's every movement.
A very disturbed youngster called Leo Smith (Lydon) arrives at O'Connor's door and convinces him that he's the notorious "copkiller" and is responsible for a continued killing spree. O'Connor beats, subdues and kidnaps Smith and starts to think how to murder him, but when Carvo appears and finds out about Smith, the partners have a struggle and O'Connor accidentally kills Carvo instead. He decides to make Smith his accomplice in the crime, and after that Smith becomes a permanent "guest" of O'Connor, trapped inside but living freely in O'Connor's apartment, with no indication of a change in the strange situation.
O'Connor starts to feel the guilt over his actions, while at the same time he gets closer to Carvo's widow, Lenore (Garcia), shifting from interested friend to romantic interest. A bizarre cat-and-mouse game develops between O'Connor and Smith, with the first trying to direct the course of O'Connor's actions to prevent any more inquiries on Carvo's death, and the latter investigating if his enigmatic cohabitant is the real cop killer. The mind game contorts until the one-upmanship reaches a climactic end.Harvey Keitel ... Lt. Fred O'Connor
John Lydon ... Leo Smith
Nicole Garcia ... Lenore Carvo
Leonard Mann ... Bob Carvo
Sylvia Sidney ... Margaret Smith
The premiere in Italy was on March 15, 1983. Since then, this rarely seen film has become part of the public domain. Because there is no true owner of the footage, scores of bad-quality copies are floating around the market. Some few legitimate copies of the film were released in a mid-1980s VHS by Thorn EMI Screen Entertainment under the title Corrupt. Several imprints with the title Cop Killer or Copkiller are poorly made transfers and there has been no official DVD release either; most of the copies in this format are badly edited and sourced from the same VHS that came out in the 1980s.
The film is marketed under various titles, including The Order of Death or Order of Death (mostly in the United Kingdom), Corrupt in USA, Cop Killer or Cop Killers in Europe, Bad Cop Chronicles #2: Corrupt (from the VHS sleeve, part of the video series Bad Cop Chronicles) and Corrupt Lieutenant. The latter was devised after 1992 to capitalize on Abel Ferrara's Bad Lieutenant, a critically acclaimed film also featuring Harvey Keitel.
Copkiller was reviewed on BBC 1's Film 83 as Order of Death. Well-known British film critic Barry Norman refers to Lydon's voice as a “speak-your-weight machine", and sums up by calling the movie "stupid".
In the book Harvey Keitel Movie Top Ten edited by Creation Books in 1999 and compiled by film author Jack Hunter, featuring his personal "Top Ten" of Keitel's best films or performances, there is a chapter dedicated to Copkiller. The chapter is written by film critic David Prothero, who describes the film as "undoubtedly one of Kietel's finest films". Prothero makes the link between Keitel's character in the film and his character in Bad Lieutenant. Another comparison he brings is the parallel relation between Copkiller and Lydon's role with the relation drawn from the film Performance and Mick Jagger's role there; Prothero describes the blurring of Lydon's stage persona with his onscreen character, stating that defining proofs about this hypothesis are Leo Smith's tantrums ala Johnny Rotten, his mixture of arrogance and cynicism and the fact that Lydon wears his own clothes throughout the film.
Harvey Keitel's portrayal of a corrupt cop has been pointed out as a prototype of his subsequent character of The Lieutenant in the cult classic film Bad Lieutenant, because of their similarities; particularly in the depiction of self-blame. In the aforementioned chapter of Harvey Keitel Movie Top Ten, by David Prothero, this comparison is mentioned.
John Lydon's Post-punk group Public Image Ltd (PiL) was supposed to score the soundtrack for the film and worked on the material with his band mates Keith Levene and Martin Atkins (over the phone, by long distance).
In early November 1982 PiL announced the imminent release of a new single, Blue Water, and a six-track mini album, You Are Now Entering A Commercial Zone, on their new label, which was supposed to release the unused music for Copkiller. This did not happen, with the band instead continuing to record a full-length album at South Park Studios.
In mid-1983 in PiL's absence, Keith Levene took the unfinished album tapes and did his own mix. He then flew over to London and presented them to Richard Branson as the finished new PiL album for Virgin Records: Commercial Zone. For his part, John Lydon decided to completely abandon the tapes and re-record the whole album from scratch with session musicians. This new version of Commercial Zone became This Is What You Want... This Is What You Get in 1984.
The classic new wave song The Order of Death from This Is What You Want... This Is What You Get is a reference to the film. The line "This is what you want... This is what you get", which gives his title to the album, appears in The Order of Death.