Transcript for Killing Bin Laden
Now to a remarkable first hand account to the Navy S.E.A.L. Who sails he was the one that killed Osama bin laden. You'll remember the images from inside that compound after the raid. And we thought we'd might never know how it went down. Tonight, we do. ABC's chief global affairs correspondent Martha Raddatz. Reporter: Abbottabad, Pakistan, may 2nd, 2011. The bin laden compound, quiet on this moonless night, as S.E.A.L. Team six moves in. S.e.a.l. Rob o'neill saying the team had not originally been told who the infamous target would be. They told us a couple of things, like, we're going to read new eventually, here's who is going to be there. They said a few names that didn't make sense. A few of us were talking a couple days later about this person. This person. Why would they be there? It's bin laden, they found him. We're going to go get him. Reporter: No sooner had they begun the descent, one of the helicopters crash lands. And while officials watched anxiously, in real time from the white house, o'neill revealing, in a special tonight on Fox News channel, that as the S.E.A.L.S made their way upstairs to bin laden's bedroom, the team feared they would not make it out alive. The more we trained on it, the more rerealized, this is going to be a one-way mission. We're going to go and we're not going to come back. We're going to die when the hosue blows up, we're going to die when he blows up. Or we're going to be there too long and get arrested by the Pakistanis and we're going to spend the rest of our short lives in Pakistani prison. Reporter: But a different scenario played out that night, o'neill says he found himself face to face with the terror master mind, telling "Esquire" magazine he could clearly see bin laden's features through the night vision goggles, that he ws "Way taller than I was expecting." In that split second, o'neill says he fired twice into bin laden's forehead, killing him instantly, telling "The Washington post" -- "I watched him take his last breath." Reporter: One of the other S.E.A.L.S there that night, Matt Bissonette tells a different story. Matt Bissonette says it was the pointman on the team that fired the fatal shot. O'neill sails the pointman either missed or just wounded bin laden. That S.E.A.L., the pointman, has yet to tell his story. David? All right, Martha Raddatz in Washington tonight. Martha, thank you.
This transcript has been automatically generated and may not be 100% accurate.