A noted 1960s San Francisco-area radical who provided guns and training to the Black Panthers was an FBI informant, according to the Center for Investigative Reporting.

In addition to spying on the Panthers since their founding in Oakland, Richard Masato Aoki also fed the feds information about the Communist Party, Socialist Workers Party and its Young Socialist Alliance, CIR says, citing the FBI agent who recruited Aoki and agency documents.

"He was my informant. I developed him," former FBI agent Burney Threadgill Jr. told reporter Seth Rosenfeld. "He was one of the best sources we had."

The revelation emerged while Rosenfeld was researching his book Subversives: The FBI's War on Student Radicals, and Reagan's Rise to Power, which will be published Tuesday.

When asked in a 2007 interview whether he was FBI informant "T-2," Aoki's first response was a long silence. He then replied, '"Oh,' is all I can say," though he later "contended the information wasn't true," Rosenfeld writes.

An FBI spokesman wouldn't comment, citing a Freedom of Information Act lawsuit that seeks more records about Aoki.

In an interview this afternoon with KQED-FM, Rosenfeld said there was no evidence that the FBI provided any of the weapons.

Aoki, who was the "minister of education" for the Berkeley chapter of the Black Panthers Party, killed himself in 2009 at age 70 after a long illness. For a quarter-century before, he was a teacher, counselor and administrator at the Peralta Community College District in Alameda County, Calif., and was active in civil rights issues.

He is the subject of a 2009 documentary film, Aoki, and a biography published this year, Samurai Among Panthers.