Not sure if this was asked in another question. In one scene, in the night near the water where there are white rats, John says he has seen the place before. He is also being tracked by the police. Could John have been the serial killer and the midget lady takes her revenge for killing her daughter or somebody by killing John?
shareIt is certainly a plausible reading of the film, and yes it does occasionally come up on other threads. There are several hints throughout the film that John is the serial killer. When he and Laura pass a murder scene on the boat she turns to him and asks "I thought this was the place where...isn't this where you were.." and he swiftly rebuffs her with a "no". The inspector then has him followed later in the film. At the end it is possible the dwarf was defending herself against him (he chases and corners her remember).
In the book the dwarf is definitely the serial killer and John is definitely the victim, but the film certainly goes out of its way to make it ambiguous.