Law & Order: Criminal Intent Season 5 Episode 11

Slither

After Russ Corbett and his wife are found in a seedy hotel room, Russ dead of an overdose, Eames and Goren follow the trail of evidence to Bernard Fremont, a professional partier. With his beautiful blonde companions, Fremont insinuates himself into the lives of couples who don't know the city very well, then robs them blind. While investigating Fremont's past in Asia, Goren realises that he is the mastermind that turned Nicole Wallace into a murderer, and his most successful pupil.