When the CBI are called in to assist the San Francisco police in a homicide investigation, Jane and the team quickly find themselves at the forefront of a search for a serial killer. Their initial suspect seems good for it - he's a guilty-looking man without a concrete alibi who refuses to cooperate with law enforcement. Jane, however, believes they have the wrong guy. With the help of a citizen who runs a web site dedicated to finding this killer, (mirroring Jane's obsession with Red John), Patrick begins exploring alternative suspects.