In mysteries/crime fiction, the obvious antagonists are the villain and the sleuth. But that’s only the beginning. Until the villain is discovered, every suspect is an antagonist. Those who apparently cooperate may be lying. Those who lie may do so to protect themselves or to protect others. In the latter case, the liar may be acting on knowledge or on fears and suspicions—guesswork—and the basis of the lies may have nothing to do with the crime in question. For instance a murder investigation may turn up blackmail, as in my Styx and Stones and A Mourning Wedding , with several characters trying to conceal the reasons they are vulnerable to blackmail. Those who don’t cooperate are obstructive. Again, this behaviour may be self- or other-protective, with the same caveats, or may be sheer bloodymindedness. All these, for their many and various reasons, are antagonistic to the investigator, whether amateur or professional (though one advantage of an amateur sleuth is that peopl...