Mark Feldstein of George Washington University, who is writing a book on Anderson's Nixon-era exposes, said FBI agents sought the information in March in the prosecution of two ex-lobbyists with the American Israel Public Affairs Committee.
Steven Rosen and Keith Weissman were indicted in August on charges of receiving and transmitting national defense information.
Feldstein told The Washington Post he was surprised the FBI agents mentioned the case when they asked about reporters who worked for Anderson who were pro-Israel or close to the AIPAC.
Feldstein "tried to wave (FBI agents) off" when they mentioned specific reporters' names, the Post said.
The agents also wanted to know if Anderson's files contained classified documents relating to Israel and Iran as early as the 1980s. Feldstein said no classified documents have been found in nearly 200 boxes of Anderson's records.
The FBI said it will continue efforts to see Anderson's files, a move Anderson's family has fought.