Cynthia Kereluk

A couple live in an old, isolated mansion. The husband's murderous, insane twin escapes from a lunatic asylum. The cops haul off the wrong twin and the wife is stuck with the killer.

It's about a serial killer with terminal cancer who leaves numbered cards on his victim's bodies, a girl who falls in love with him, a loser cabbie who becomes the prime suspect, an old asshole police sergeant, and a radio reporter who takes the law into his own hands.