Who is Tarrance from The Firm and what is their importance?

Wayne Tarrance is an FBI agent. He was transferred into the Memphis area from New York approximately two years before Mitch's employment at the Bendini, Lambert and Locke law firm. Prior to working with Mitch, he had earned the trust of Kozinski and Hodge, who were in the process of providing Tarrance with information about the firm when they were mysteriously killed. Tarrance is Mitch's main contact from the FBI, but he is assisted by agents Acklin, Jenkins, and Harbinson.