Calman Clayburn is a Special FBI Agent who, as a favor to Switek (due to his busting Clayburn's nephew dealing drugs at a UB40 concert), provided vital information to Crockett and Tubbs about FBI Agent Arthur Lawson and his current status. Switek planned to use Clayburn's favor as a stepping stone to a federal job, but after this, Clyburn declared he and Switek even.