"Nothing to do with me? This punk kid took my daughter."
Little is known about Jack's past, other than he finally admits to have been a hitman with the McCrellan Corporation, a predominantly Irish mob in Boston, and the trial against the "corporation" is going to begin in two weeks. He and his daughter Lindsey were in the witness protection program for ten years, under the protection of U.S. Marshal Pat Mannan. His wife was later killed in a car crash intended to kill him. Considering he was in witness protection, it is extremely likely that Jack Vaughan isn't even his real name.
Lindsey and her friend, Katie, were approached at a movie theater by three males, one of whom Katie had a crush on. While Katie wanted to go with them, Lindsey didn't trust them but went anyway because she was protective of Katie, who would later be tortured and strangled to death in an abandoned house by the leader while Lindsey was forced to watch. The BAU is called in to assist in the investigation and are unaware that Jack is a hitman. They later discover that Mannan is a U.S. Marshal when Morgan sees a gun on him while he is struggling to restrain Jack, just after Reid discovered that the personal history they have been sharing with their friends and acquaintances is a direct extrapolation of the plot of a novel, including the names they are using. At the police station, Bruce Owens, Katie's father, knows the dead suspect, as well as who his friends are, and asks Jack if he is still up to doing what he "used to do".
Jack then overpowers Mannan, disappears, and meets up with one of the abductors, shooting him in the leg with a Remington 870 shotgun. After questioning the injured young man, Jack is told the location of Lindsey and her abductor, Ryan Phillips. Meanwhile, Reid ascertains the location himself and rushes to meet the rest of the team there. When he arrives, he sees Jack holding Ryan at gunpoint as his daughter looks on. Reid tries to get Jack to drop the shotgun, but Lindsey begs her father to kill Ryan. Jack agrees that he needs to make changes in his life to make a better life for his daughter. Reid asks, "When is the violence going to end?" Jack replies, "Tomorrow." He pulls the trigger, killing Ryan. The rest of the team arrives with Mannan, and they reason that what happens to Jack depends on how important of a witness he is. Jack is later seen living a new life with his daughter in Atlanta, Georgia. They meet a pair of neighbors, a father and his daughter. Both the men and the girls shake hands and Lindsey introduces herself as "Katie".
Jack will reappear in this episode.
- Killed numerous unnamed victims during his time as a hitman
- January 7, 2008: