Whats this movie called?

The movie was about I think a guy and a killer and i think the guy saw the killer kill someone and the killer tries to find him and kill him. I remember a scene towards the end when a cop goes to an amusement park or a beach with another cop who's actually working for the killer, and the guy's hiding in a beach house. the killer radios the bad cop saying that he almost found the surfer and needs help and the good cop hears it and handcuffs him to a railing. a bunch of kids look at him and he said something like " it's okay I'm a cop. and he's a very bad man." lol sorry for the lame description. haven't seen it since i was little. Please help me find the name of this movie.