"I have seen no evidence at all that the senior leadership knew. In fact, I have seen some evidence to the contrary. But we have no evidence yet with respect to anybody else. My supposition is: Somebody knew," Gates told reporters at a Pentagon news conference.
"The supposition is somebody. We don't know whether it was, you know, a retired people, whether it was low-level. We have pure supposition on our part. It is hard to go to them with an accusation when we have no proof that anybody knew," he said.
"So I just want to underscore, it's my supposition. I think it's a supposition shared by a number in this government that somebody had had to know, but we have no idea who, and we have no proof or no evidence," Gates asserted in response to a question.
"With the evaluation of the sensitive site material and exploitation that's going on, it's just going to take us a while to see if there's anything else," said Admiral Mike Mullen, Chairman of the Joint Chiefs of Staff at the same news conference.
"I have seen no evidence that the top leadership knows," he said.