At least six people were killed and more wounded. Rep. Gabrielle Giffords, D-Ariz., was in critical condition this afternoon following emergency surgery for a bullet wound to the head.
Dr. Steven Rayle told "CBS Evening News" anchor Katie Couric that he saw the shooter "spraying everybody at point blank range. It wasn't like he was picking people out; he just began shooting at everybody who was close to him [in] kind of a constricted area."
Dr. Rayle said there were about 20-25 people in attendance. "So probably at least half of the people were shot," he said.
He said he did not hear the suspect yell anything. "He had a determined look on his face," Dr. Rayle said. "And he just began shooting."
The gunman, whom police have identified as Jared Loughner, 22, was tackled and apprehended. "I think he really thought he would be getting away," he said.
After the gunman was subdued, Dr. Rayle helped render aid to some of the people that were shot, but said that several "were clearly mortally wounded right away."
The doctor checked on the condition of Rep. Giffords: "She was conscious, I was very encouraged because she was sitting - someone had propped her sitting up, was tending to her - and I could see she had blood on her face and a head wound, but she was moving her extremities and was conscious, so I was very encouraged that it was not a fatal wound."
He also witnessed a young girl being treated for a gunshot wound; she later died. "[She] was being given CPR, but again, CPR in a gunshot trauma is the last-ditch effort kind of thing."