CBS News national security correspondent David Martin reports the 40 minutes it took to kill bin Laden and scoop his archives into garbage bags were all recorded by tiny helmet cameras worn by each of the 25 SEALs.

Officials reviewing those videos are still reconstructing a more accurate version of what happened. We now know that the only firefight took place in the guest house, where one of bin Laden's couriers opened fire and was quickly gunned down. No one in the main building got off a shot or was even armed, although there were weapons nearby. 

The SEALs first saw bin Laden when he came out on the third floor landing. They fired, but missed. He retreated to his bedroom, and the first SEAL through the door grabbed bin Laden's daughters and pulled them aside.

When the second SEAL entered, bin Laden's wife rushed forward at him -- or perhaps was pushed by bin Laden. The SEAL shoved her aside and shot bin Laden in the chest. A third seal shot him in the head.

The top Democrat on the House Intelligence Committee went to CIA headquarters Thursday to view photos the SEALs took of bin Laden's body.

"There were probably about maybe four, five or six photos," said Rep. C.A. Dutch Ruppersberger, D-Md. "There are just a couple body shots. He was like, in a white undershirt and a tan robe."

The electronic files the SEALs carted away from bin Laden's compound contain -- among many things -- the names of terrorist operatives which until now were unknown to U.S. intelligence. The files also contain a small, 12-page journal of bin Laden's handwritten notes about launching a major attack against the United States. He instructed against using Arabs because they arouse too much suspicion, to go after trains and to time the attack to coincide with the 10th anniversary of September 11. 

There are also messages to his senior lieutenants and to al Qaeda affiliates, urging them not to waste time on small, local operations and focus their efforts on the United States.

Ruppersberger said, "He kept all that information and he kept all of the data, computers, hard drives and this is what we're analyzing and it shows that his focus was clearly the United States."

U.S. officials cannot understand why bin Laden apparently left what amounts to the keys to his terrorist kingdom just lying around his compound in plain sight -- none of it rigged for self destruction.The killing of Osama bin Laden

Why didn't bin Laden protect his files? The best guess is he thought the United States would never find him.