D-Tox

Sylvester Stallone stars as Jake Malloy, an FBI man whose girlfriend is murdered by a serial killer, and whose subsequent retreat into the bottle lands him with a stay in a remote Wyoming detox clinic. Not long after he arrives, two of the clinic's patients are discovered dead, and Malloy begins to investigate. It doesn't take long for him to realise that the man who killed his girlfriend is staying with him there in the clinic.

The only question is: which one of the patients is it?