S2, E12: When Don and his team are called to the murder scene of a Los Angeles gang member, they learn that the victim is a fellow agent who had been working undercover. Without exposing the agent's cover, Don must investigate his murder by a rival gang and try to crack the gangs' leadership and territories to find the suspect. However, the agents are surprised when they learn who is responsible for the source of the rivalry. Will Patton guest stars.