Papertrail

Papertrail is a 1998 Canadian thriller film produced, co-written and directed by Damian Lee, starring Chris Penn, Michael Madsen and Chad McQueen. In it, a loner detective is brought back to the unsolved serial killer case that once destroyed his social life, when he is asked to attend a therapy group whose psychiatrist has been receiving phone calls from the perpetrator. On North American home video, the film was renamed Trail of a Serial Killer, while it is known as Serial Cops in the U.K.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.