I can't remember the title of this movie!!!?

Its about an english cop who moves from london to a little small town, because he is too good of a cop. He is super strict, and the towns police force is really lax. He gets assigned a fat funny side kick who is like the son of the chief of police. THe plot of the movie is the strict main character cop trying to prove that what is believed to be a string of strange accidents, are actually clever murders. The town watch end up being responsible for the murders, and he goes all crazy rambo style on them. The town watch like meet at night and wear creepy black robes and plan to kill people who play music too loud, or wear their pants too low. If anyone can remember the name of this movie, please tell me! Its driving me crazy!