Apart from a couple of parodies of Raymond Chandler stories, I’ve never written a detective story. Therefore, I have no authority as a writer to say what I'm about to say. But I definitely have authority as a reader or viewer. This is the issue: I almost always feel short-changed. For example, I recently watched a tv series, five episodes in all, and the killer was revealed in the last 10 minutes and a rogue cop in the last 5. There were no clues to help the viewer work out whodunnit. Quite frankly, it strikes me as supremely lazy writing.