Dark Water (2001)

A psychological drama. It is the story of a young man who, through a series of surreal visions, comes to believe that he is a serial killer targeting pedophiles. The film explores the consequences of someone taking action on such familiar impulses as "If any one of those creeps ever tried to touch one of my kids, I'd..." The killer is pursued by the unconventional Inspector Skallen, who champions the controversial new technique of geographic profiling.