When a bisexual woman is slain, Detectives Goren (Vincent D'Onofrio) and Eames (Kathryn Erbe) note similarities between an incarcerated serial killer's (guest star Jack Gwaltney) methods -- prompting them to suspect a mousy human-behavior researcher (guest star Jenny Bacon) might have fallen under his spell and committed the copycat murder. However, while D.A. Carver (Courtney B. Vance) stalls to prevent the release of the imprisoned man, the detectives discover a hitch in their theory that might point to a most unlikely suspect. Jamey Sheridan also stars.