Allan H. Ryskind, here:
The FBI had opened a file on Oppenheimer as early as 1941, after he had failed to immediately inform superiors that three men in Berkeley, California, had been solicited to obtain nuclear secrets for the Soviet Union and that both he and his brother Frank had been urged to help them. One of his colleagues at the University of California at Berkeley was Haakon Chevalier, who worked with Oppenheimer on various Communist enterprises and who urged him to give Soviet Union Premier Josef Stalin what he wanted.
The Bureau opened its file on Oppenheimer after he had attended a December, 1940, meeting at Chevalier's home that was also attended by the Communist Party's California state secretary William Schneiderman and its treasurer Isaac Folkoff, each of whom was being wiretapped by the FBI.
In early 1943, Chevalier had a brief conversation with Oppenheimer in Chevalier's kitchen, with Chevalier mentioning that a scientist, George Eltenton, could transmit information of a technical nature to the Soviet Union about our progress on the highly secretive atomic bomb project that Oppenheimer was working on.
He initially rejected the overture to assist Eltenton but failed to report the incident until August of 1943. His failure to promptly report what was clearly a Soviet espionage effort would become central to the decision to revoke his security clearance. Oppenheimer did not report the recruitment effort until six months later. In subsequent interviews with Army security, he admitted he had been approached, but he refused to name Chevalier or anyone else who might have been involved. Not until December, 1943, in response to a direct order from Groves, did he name Chevalier.
From 1937 to 1942, he was a member at Berkeley of what he called "a discussion group," which was later identified by fellow members Chevalier and Gordon Griffiths as a "closed" or "secret" unit of the Communist Party for Berkeley faculty.
