When a young woman is found dead, she is initially believed to be a prostitute and the latest victim of a serial killer. As they look into her home life, however, Benson and Stabler realize that the victim does not fit the pattern, and may not be connected to the other deaths after all. After Munch's instincts lead the team to believe their suspect is a cop, Cragen consults his old friend Det. Lennie Briscoe for help.