AMANPOUR (voice-over): This morning, we are live from the scene, as the nation absorbs the horror of a gun attack in broad daylight on Congresswoman Gabrielle Giffords.
(UNKNOWN): Gabrielle Giffords was going out practicing that First Amendment right that she had, and some bastard shot her down.
AMANPOUR: Six are killed by an Arizona gunman, and Congresswoman Giffords is fighting for her life. Twelve more are shot and wounded, and the questions have started: How did this happen? And why did this happen?
(UNKNOWN): I hope that all Americans are saddened and as shocked as we are.
AMANPOUR: We have the latest details on the search for the alleged accomplice, the eyewitness accounts, and all the analysis of a shocking crime.
(END VIDEO CLIP)
ANNOUNCER: A special edition of "This Week" with Christiane Amanpour, "Tragedy in Tucson," starts right now.
AMANPOUR: This morning, we come to you live from the University Medical Center in Tucson, Arizona. Yesterday, in this desert town, a gunman opened fire during a meet-and-greet political event at a local supermarket not far from here.
Six people are dead. Among them, a federal judge and a 9-year-old girl.
The primary target was Congresswoman Gabrielle Giffords. She was shot in the head and is still in critical condition after surgery in the building behind me.
The gunman is in custody. Police are searching for a possible accomplice. And now the questions mount: What triggered this tragedy in Tucson?
(BEGIN VIDEO CLIP)
AMANPOUR (voice-over): It started just after 10 a.m. Saturday, Tucson time. Congresswoman Giffords had been holding a town meeting with constituents in this parking lot of a local Safeway.
Alex Villec, a young volunteer, was standing about three feet away from her.
VILLEC: Kind of a shady-looked gentleman came up, asked me if he could talk to the congresswoman. So just like anybody else, we directed him to the back of the line. He came back about 30 seconds later, and before I knew, he was barging through the -- through the tables toward the congresswoman.
AMANPOUR: Steven Rayle was there, too. A local doctor, he had come to meet Giffords and saw a man with a blank expression on his face.
RAYLE: I looked up and saw a man with a gun shoot her in the head and then continue firing, rapid-fire, with just point blank at everybody who was in the area. And there's really nowhere to -- to run. I laid on the ground as if I had been shot in order to -- to not be a target.
AMANPOUR: Rayle says that, when the shooting stopped, many who weren't hurt leapt into action.
RAYLE: The shooter was actually tackled by one of her aides, and several people were holding him down.
AMANPOUR: Rayle, a former E.R. doctor, started treating the wounded.
RAYLE: It was very apparent that -- that at least three of the people were mortally wounded right away. One guy was on his face and unresponsive.
AMANPOUR: He saw a young girl. It turns out she was 9-year-old Christina Taylor, who had come to the event with a neighbor.
RAYLE: She was unresponsive. And, as a medical person, it did not look good.
AMANPOUR: Also shot and bleeding, federal Judge John Roll and several of Giffords' aides. Dr. Rayle went over to check on the congresswoman.