The publicity concerning Tsien's luggage couldn't have come at a worse time for him. It coincided with the trial of Sidney Weinbaum, which began August 30 and lasted until mid-September.
The military had long suspected Tsien and his friends of Communist activities-as early as 1941. The accusation first reached Sidney Weinbaum sometime during that period, when he was working for the Bendix Corporation. During a big party at the Caltech aeronautics department, Professor Clark Millikan informed Frank Malina that he -- Millikan -- had heard that Malina and Weinbaum and two or three other people were members of the Communist Party. The FBI, apparently, had given Millikan the information. Recalled Weinbaum: "So I went to see a lawyer friend of mine and said, 'What can I do?' I was sure that with an accusation like that they were going to refuse me clearance. But no! I was cleared throughout all these years; from '41 to '49, when the trouble began, I was cleared for top-secret work." In the early 1940s, Army Intelligence heard accusations that Tsien was a Communist as well, but no effort was taken to suspend his clearance either. On the contrary, he was granted permission to work on projects classified "restricted," "confidential," and even "secret."