6x5 - Wire in the Blood

Two young men are found murdered, the only connection being that skin from one of them is found under the other's fingernails. As other bodies are found, Tony deduces that a sadistic gay murderer is abducting white boys and forcing them to kill each other. Meanwhile Michael Bryant, the cannibal killer whom Tony helped to put away, sends him a message from the secure unit where he is incarcerated, telling Tony that he is planning to escape and will see him soon.