what is that movie that there are people in an island and there was a serial killer who i think was the police.. there was a scene where someone hid under the bed but then got killed.. the ending was that the killer was killed butt the funny thing is that even though his body got cut in half, his lower part(legs) were still moving and paddling in the water.. please i need help. i want to watch that movie again.. i watched it years ago and i cant remember the title now.