Chain of Evidence (1999)

All the clues gathered by the profiler point to one man: himself - David Bornett is a profiler for the criminal police, and he's the best they come. A little too cocky, a little too sure, he's got a theory for every murder and finds the killer practically every time. Shortly after his godson Michael joins his team, a serial killer begins to stalk the area, leaving a police ball-point pen embedded in the victim's bodies as his signature. While David is sure that the killer is in the police force, Michael goes one step further and suspects David of being the killer. On a secret campaign to find David's weak spot, Michael stumbles across a psychiatric report according to which David once suffered from a multiple personality disorder.