Law & Order: Criminal Intent Season 1 Episode 18

When the well-preserved body of a woman tortured and murdered twenty years earlier appears on the banks of the Bronx River, chemical residue on the body leads Goren and Eames to the basement of the house in which the body had originally been buried and to the junkie whose parents owned the home. When the junkie ends up murdered as well, their investigation focuses on his college classmate, a man with a history of drugging and sexually assaulting women.