The trajectory of Willie Doherty’s photographic work since the early ’80s, as well as his subsequent work with slides and video, resembles that of a dissatisfied detective who repeatedly returns to the scene of an insoluble crime. Or perhaps it more closely resembles that of the perpetrator of the crime who falls prey to a similar urge. It is no coincidence that this very ambiguity lies at the heart of one of Doherty’s most powerful installations, The Only Good One is a Dead One, 1993, in which a voice-over monologue switches unnervingly between the point of view of an assassin and that of his