After Aderholt discovers the bug in the Mail Robot, Loeb and Agent Ganzel monitor it and arrest a janitor who is switching out the tapes. He's part of the team led by Stan trying to find a KGB source in a lab that makes pathogens. He gives Stan the employee list for Foster Medical Lab which they later discover William Crandall works at and is the KGB source. ("A Roy Rogers in Franconia")
In November 1987, he's part of the team investigating "Illegal" Dan Murton, aka "Harvest", and asks Aderholt about wire-taps on Murton. ("Rififi") He looks on as Agent Loeb gives Stan an update on getting records from a company. ("Harvest") Ganzel gives an update on surveilling Russian Orthodox priests including Father Viktor. ("The Summit") Aderholt re-assigns all agents, including Ganzel, to surveil garages suspected of being used by the Illegals. ("Jennings, Elizabeth") Ganzel surveils a garage with Stan not knowing that he confronted and allowed the Jennings to escape. ("START")