Someone in Pakistan knew about bin Laden's hideout: Panetta

US Defence Secretary Leon Panetta has said he still believes someone in authority in Pakistan knew where Al-Qaeda leader Osama bin Laden was hiding before the US raid on his hideout.

Bolstering his hunch were intelligence reports of Pakistani military helicopters passing over the compound in Abbottabad, near the Pakistani capital of Islamabad, where Navy Seals found and killed bin Laden last May, he said in a TV interview to air Sunday.

"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 told CBS News.

Explaining why Pakistan was not made aware of the US raid on the compound, Panetta said:

"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."

Asked whether he knows for sure that the government of Pakistan knew where bin Laden was, he said: "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 also acknowledged that Shikal Afridi, the Pakistani doctor conducting health tests in the village in an effort to collect DNA and verify bin Laden's presence, was in fact working for the US. Afridi was arrested and charged with treason by the government of Pakistan.

"I'm very concerned about what the Pakistanis did with this individual...who in fact helped provide intelligence that was very helpful with regards to this operation," he said.

"He was not in any way treasonous towards Pakistan...Pakistan and the United States have a common cause here against terrorism...and for them to take this kind of action against somebody who was helping to go after terrorism, I just think is a real mistake on their part," he said.