On June 20, 1972, Cahill was called by Rufus Carlin. He then ordered Carlin to find and destroy the "doc". He was then called again by Rufus and told to kill the the "Doc". When Rufus called him a third time, Carlin sent a team to assist in taking the Doc out. (“The Watergate Tape”)
Benjamin Cahill is also Lucy Preston's father. He also has an unnamed son.