Cop is based on the book 'Blood and the Moon' by James Ellroy. I have not read the book that the film is based on; although I am a big fan of the first three books in Ellroy's 'L.A. Quartet'. It is often said of Ellroy that his writing got better as it went along; and assuming that this film is closely based on the book, I would say that there's a good chance that is true as the story here is not exactly solid. The entire film hinges on one major and quite unbelievable coincidence that boggles the mind if you care to think about it. However, it's the style and atmosphere that saves it; and that's the main reason I loved this film! The plot focuses on your everyday hard-bitten cop, Lloyd Hopkins, who after investigating the murder of a woman in Los Angeles, comes to believe that a serial killer may be operating in the area. Naturally, the police captain doesn't believe a word of it and Lloyd is forced to investigate on his own; leading him to a revelation closer to home than he was expecting.<br /><br />Director James B. Harris creates a fabulous atmosphere for the film to take place in and ensures that L.A. seems to be every bit the gritty and sleazy location needed to facilitate a tale like this. Similarly, James Woods fits the central role like a glove and is always believable in the role; even when the plot is getting out of hand. The first half of the film is really rather good and plausible; but then the twist hits and it really requires a suspension of disbelief from the viewer. It's not that the twist could not happen; it's more the way that it does happen which comes off as silly. It's just far too convenient and the whole film is turned on its head from that point on. Still, the atmosphere is retained and the story continues to be gripping; which are the film's strongest elements. Certain elements of the film are rather nasty, and indeed the book was originally denied by many different publishers for being too graphic! Still, a lot of it focuses on dialogue and from what I know of Ellroy, this part of the film is quite faithful. It all boils down to a rather hurried and coincidental ending; but I really do feel that this is a film where the style of it is much more important than the plot line. For some it will no doubt be too much of a problem...but I wouldn't hesitate to recommend this to anyone that enjoys a good crime thriller!