Bulger's lead attorney, J.W. Carney Jr., has repeatedly complained that prosecutors have turned over documents in a disorganized fashion. Prosecutors have accused Carney of using stall tactics.
Bulger fled Boston in 1994 and was captured last year in Santa Monica, Calif.
The defense says Bulger was an FBI informant who had immunity to commit crimes while he was providing information about the Mafia, his gang's main rival. In court papers filed this week, Carney identified former U.S. Attorney Jeremiah O'Sullivan as the federal official Bulger claims gave him immunity. O'Sullivan died in 2009.
Prosecutors say Bulger never received immunity from anyone.