S6, E11: The city anxiously anticipates the arrival of Heather Taffet, more notoriously known as “The Gravedigger,” for her final appeal after being sentenced to death for a kidnap-murder and a series of similar coldblooded crimes. But when a bullet targeted at The Gravedigger is fired from a distance and hits her, the Jeffersonian team is tasked to piece together the sniper’s precise location as well as identify the suspect and his motives. With the help of probing investigator Caroline Julian (guest star Patricia Belcher), Booth and Brennan put together a list of likely suspects, but the evidence and the remarkable skill needed to pull off the crime leads the team to believe that the crime was an inside, professional job, leaving Brennan’s father Max (guest star Ryan O’Neal) and even Booth as plausible suspects. Meanwhile, Sweets attempts to put on a brave face after being caught in the firestorm just moments following a chilly encounter with The Gravedigger.