Bill Jarvis is an agent from another agency, possibly CIA, who discovers the connection between Simon Gruber and John McClane.
Die Hard with a Vengeance[]
Jarvis, along with Andy Cross and the FBI Chief, met up with McClane, Zeus Carver and Special Case unit chief Walter Cobb in the car. After Cross asking them about the men in the photos, he questioned them about any unusual activity which they denied anything. McClane angrily states to him and Cross what he knows about the man name "Simon" and that he holds a grudge against him. Jarvis tells him and Zeus about Mathias Targo, a former Hungarian Army explosive expert turned freelance terrorist. He was present when Cross tells them about Targo's partner who is beleived to be killed by the Isrealis. Then Jarvis tells them about an East German Special Forces Colonel named Peter Krieg, but he is really Simon Peter Gruber, the brother of Hans Gruber. He was present when Simon called and proves that he is watching him and Cross by telling Jarvis that he can see him, crewing on his glasses. After learning about 2400 pounds of liquid explosives on one of the schools in Manhattan, Jarvis says it will take awhile to get more men from any other agencies to help find the bomb.