THE PENTAGON - The more you find out about the mission that led to Osama bin Laden's death, the more you realize what a roll of the dice it was and how close it came to disaster, CBS News national security correspondent David Martin reports.
Pulling the trigger on the operation that ended the hunt for bin Laden was one of the toughest decisions President Obama has ever had to make. Bin Laden was killed Sunday night in his hideaway in Pakistan in a raid by U.S. Navy SEALs.
Based on what the president knew -- and didn't know -- it was a very big gamble.
After months of studying satellite photos of the compound, CIA analysts concluded there was only a 60 to 80 percent chance bin Laden was really there.
In the photos, a man could be seen coming out of the main building and walking around the courtyard as if for exercise, but it was impossible to tell whether he matched bin Laden's height.
Photo interpreters analyzed the pattern of daily life and determined the family in the main building had the same number of members as bin Laden's family. None of them ever left the fortress-like compound.
It was hardly a smoking gun, which explains these words by Mr. Obama's counterterrorism adviser.
"The president had to evaluate the strength of the information and then made what I believe was one of the most gutsiest calls of any president in recent memory," John Brennan, the adviser, told reporters Monday.
That explains the tension on the faces of the president and his top advisers as they followed the mission from the White House Situation Room.
They were listening to real time reports relayed by CIA Director Leon Panetta from Vice Adm. William McRaven, head of the Joint Special Forces Command, in Afghanistan. This was McRaven's operation. He called the audibles when things started going wrong.
Four helicopters -- two Blackhawks and two Chinooks -- took off from Jalalabad, Afghanistan, 160 miles from the compound.
The Blackhawks carried 25 Navy SEALs. The Chinooks had a back-up force and extra fuel for mid-air refueling.
The SEALs planned to fast rope onto the roof of the main building right over bin Laden's head while the second helicopter dropped its SEALs into the courtyard.
But the second helicopter lost lift and had to land, clipping its tail rotor on a wall. That forced the first helicopter to change plans and land its SEALs on the ground. They now had to blast their way through walls, losing precious minutes and the element of surprise.
As the SEALs swept through the massive compound, they handcuffed those they encountered with plastic zip ties and pressed on in pursuit of their target. In all, U.S. forces found 23 children, nine women, a bin Laden courier who had unwittingly led the U.S. to its target, a son of bin Laden who was also slain, and more.
Twenty-five minutes went by. Panetta heard nothing from McRaven, and the president heard nothing from Panetta. What was supposed to be a 30- to 35-minute operation was now pushing 40.
Panetta, in interviews with Time and PBS' "Newshour," sketched the scene in the Situation Room as the tense final minutes of the raid played out.
"Once those teams went into the compound," he told PBS, "I can tell you there was a time period of almost 20 or 25 minutes that we really didn't know just exactly what was going on."
The SEALs were shooting their way up the stairs to bin Laden's bedroom. Finally, McRaven reported "Geronimo E-KIA," Geronimo -- code name for bin Laden -- E-KIA -- enemy killed in action.
Panetta told Time that when McRaven reported that the commandos had identified bin Laden "all the air we were holding came out."
In addition to bin Laden, one of his sons was killed in the raid, Brennan said. Bin Laden's wife was shot in the calf but survived, a U.S. official said. Also killed were the courier, and the courier's wife and brother, U.S. intelligence officials believe.
Now the SEALs had to get out before the Pakistanis scrambled jets to shoot down the unknown intruders. Only one Blackhawk could fly, so McRaven sent in a Chinook to help pick up the SEALs who were hauling bin Laden's body and a treasure trove of captured computers, CDs and paper files. The SEALs moved the prisoners away from the compound before blowing up the downed helicopter.
Brennan said the U.S. already was scouring items seized in the raid that might tip U.S. intelligence to al Qaeda's operational details and perhaps lead the manhunt to the presumed next-in-command, Ayman al-Zawahri.
The helicopters headed straight for the USS Carl Vinson, the aircraft carrier where bin Laden was to be buried at sea. Only then did the tension in the Situation Room begin to break. Panetta told Time that the room broke into applause.
Some people found at the compound were left behind when the SEALs withdrew and were turned over to Pakistani authorities who quickly took over control of the site, officials said. They identified the trusted courier as Kuwaiti-born Sheikh Abu Ahmed, who had been known under the name Abu Ahmed al-Kuwaiti.
When a SEAL burst into that third floor bedroom, bin Laden's wife rushed at him, so he shot her in the leg. That left bin Laden, standing right in front of him. Bin Laden was unarmed, but the SEAL thought he was still a threat, so he shot him twice, killing him with a precise shot above his left eye. He was also shot in the chest.
U.S. officials say the photographic evidence shows bin Laden was shot above his left eye, blowing away part of his skull.
The administration said this wasn't strictly a kill mission and that they would have taken bin Laden captive if he had just surrendered. The SEALs certainly weren't there to give bin Laden the benefit of the doubt, but only that SEAL knows why he pulled the trigger.