"I don't have any hard evidence, so I can't say it for a fact. There's nothing that proves the case. But as I said, my personal view is that somebody somewhere probably had that knowledge," Panetta said in an interview with CBS's "60 Minutes" to be broadcast Sunday.
Panetta said Pakistani military helicopters were reported to have passed over the compound in Abbottabad where bin Laden was found last year, CBS News reported Friday.
"I personally have always felt that somebody must have had some sense of what -- what was happening at this compound. Don't forget, this compound had 18 foot walls. ... It was the largest compound in the area. So you would have thought that somebody would have asked the question, 'What the hell's going on there?'" Panetta said.
Panetta also explained why Pakistani officials were not informed when the United States raided the compound.
"We had seen some military helicopters actually going over this compound. And for that reason, it concerned us that, if we, in fact, brought [Pakistan] into it, that -- they might ... give bin Laden a heads up," Panetta said.