JUDY WOODRUFF: To the Pakistan story.
The South Asian nation is seeing internal political turmoil and its relations with the United States shakier than ever, since the Sunday killing of Obama bin Osama bin Laden in the Pakistani city Abbottabad.
Bill Neely of Independent Television News reports from there.
BILL NEELY: Far from Ground Zero, where the mastermind of its horror was shot and killed, Pakistani troops are on guard. On the night he was killed, Osama bin Laden had almost no guard.
The unanswered question is was he that confident because he believed he was under the protection of the state, of Pakistani officials, who had reassured him he'd be safe here?
Pakistan's government says, that's wrong.
SALMAN BASHIR, Pakistani foreign secretary: This is a false hypothesis. This is a false charge.
BILL NEELY: But many in Pakistan say its spy agency, the ISI, must have known bin Laden was here.
TALAT MASOOD, former Pakistani commander: I think they definitely knew and were complicit in it. That is different as to at what level they knew and to what extent they kept it to themselves and who they were. That all has to come out, I think, through a very serious inquiry.
BILL NEELY: A former head of the ISI spy agency denies any collusion with bin Laden or al-Qaida.
GEN. HAMID GUL, Inter-Services Intelligence Agency: No collusion, no collusion, because I know the psychological makeup, the orientation of the ISI has never been pro-al-Qaida.
BILL NEELY: But it is possible someone in the ISI knew he was there?
GEN. HAMID GUL: Anything can be possible. Anything can be possible. But is it also plausible? I would say no.
BILL NEELY: Pakistan's military commanders angry at the attack, and threatening that if there's another like it Pakistan will review its military ties with the United States.
Bin Laden's Yemeni wife, who was shot in the attack, is still being questioned at Pakistan's military headquarters. She says she was at the compound for just a few months.