The Federal Bureau of Investigation (FBI) is a domestic intelligence and law enforcement organization in the United States.
Ethan Zobelle, the leader of the League of American Nationalists, is revealed as an FBI informant. Because he can name the Aryan shotcallers, and a number of judges, clergymen, and senators with ties to the League, the FBI steps in to release Zobelle from the clutches of the Charming Police Department and ATF agent June Stahl. Their investigation ultimately fails, however, as Zobelle flees the country after being released.
FBI agent Wright investigates the fallout of the L.O.A.N.-IRA connection which ended in the deaths of Polly Zobelle, Edmond Hayes, Half Sack Epps, and the kidnapping of Abel Teller by Cameron Hayes. Wright questions Tara Knowles, who witnessed the later two crimes, and later Gemma Teller Morrow, who is charged with the former pair of murders.
FBI agent Ronald Zwersky, undercover in the Russian Mafia under the alias "George Leskovich" is killed by SAMCRO alongside Viktor Putlova and several other mafia members. Following Zwersky's death, FBI agents Lane and Kessler, who knew Zwersky, are pulled from Assistant US Attorney Lincoln Potter's RICO investigation and reassigned.