U.S. Defense Secretary Leon Panetta has again raised speculation that senior Pakistani government officials were well aware that al-Qaida chieftain Osama bin Laden was residing in the country for years.

Pakistan has officially declared that it did not know bin Laden was freely living there until U.S. commandos attacked and killed the world’s most wanted terrorist at a compound near the Pakistani capital of Islamabad.

Relations between the United States and Pakistan have deteriorated ever since.

In a U.S. television interview to be broadcast on Sunday, Panetta reportedly said that he had intelligence reports suggesting that Pakistani military helicopters were seen passing over the compound in Abbottabad, where bin Laden lived, suggesting that the feared militant was being protected by Pakistan.

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.

The defense chief further explained why the raid by the U.S. Navy Seals was kept a secret from Pakistani government and military officials.

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 added, however, that he can only conjecture about Pakistan’s complicity in hiding bin Laden.

I don't have any hard evidence, so I can't say it for a fact,” he said. “There's nothing that proves the case. But as I said, my personal view is that somebody somewhere probably had that knowledge.

He also confirmed that the Pakistani doctor, Shikal Afridi, who conducted DNA evidence to verify bin Laden’s presence in Abbottabad, was indeed working for Washington. Afridi has since been arrested by Pakistani authorities on charges of treason. The government of Islamabad also claimed that Afridi was running a phony vaccination program funded by the CIA.

I'm very concerned about what the Pakistanis did with this individual [Afridi] ... who in fact helped provide intelligence that was very helpful with regards to this operation, Panetta 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.”

American officials have demanded that Afridi be released and allowed to move to the United States.

Panetta’s interview will be broadcast on Sunday evening on CBS' “60 Minutes” program.