Arizona Rep. Gabrielle Giffords' "Congress on Your Corner" event started much like dozens of her previous meetings with constituents: in a supermarket parking lot with two dozen people assembled. Only this time, a gunman stepped forward.
The shooting Saturday morning was so fast that there was barely time for people to scream before they fell, witnesses said. When it was over, six were dead and 12 were wounded, including Giffords, who was shot in the head.
The suspected gunman was identified by police as 22-year-old Jared Lee Loughner. Police say the shooter may not have acted alone, and witnesses said he fired at close range with a semiautomatic pistol and was preparing to reload when two onlookers tackled him.
By that time, U.S. District Judge John M. Roll, who had stopped by the event to say hello to Giffords, was dead, as was Gabe Zimmerman, 30, the congresswoman's director of community outreach.
Also killed were Dorothy Murray, 76, Dorwin Stoddard, 76, and Phyllis Schneck, 79. A 9-year-old girl died at the hospital.
Giffords' chief of staff, Ron Barber, and staffer Pam Simon were shot but were expected to recover. Giffords was conscious and responsive after brain surgery, though former U.S. Surgeon General Richard Carmona, a family friend, said she had suffered a "very devastating ÃƒÂ‚Ã‚Â… very severe" injury.
"They were operating like a combat casualty hospital," Carmona said of the University Medical Center, where many of the injured, including Giffords, were taken.
"It was a lot of shots, a slurry of shots," said David Beal, a retired obstetrician who was waiting to greet the congresswoman when the gunfire erupted. "It was really horrendous. She was kind of crumpled on the sidewalk," he said. "I just told the guy who was with her to keep her head up, and I gave him my sweater, and he put it under her head. He kept holding her. All you can do with a head wound is to keep her head up."
"He was just spraying gunfire, and people were at close enough range that he was taking them out, effectively," Steven Rayle, a former emergency room physician who attended the event and helped treat the injured, told CNN.
At least two witnesses said paramedics took about 15 minutes to arrive, though sheriff's deputies were on the scene almost immediately.
Pima County Sheriff Clarence W. Dupnik did not ascribe a motive to the shooting but lashed out at what he called a climate of "vitriol that has permeated the political scene and left elected officials facing constant threats.
"And unfortunately Arizona, I think, has become sort of the capital," he said. "We have become the mecca for prejudice and bigotry."
He went on to point a finger at the media.
"I think it's time as a country that we do a little soul-searching. Because I think it's the vitriolic rhetoric that we hear day in and day out, from people in the radio business, and some people in the TV business ÃƒÂ‚Ã‚Â… that this has not become the nice United States of America that most of us grew up in," Dupnik said.
Referring to the increasing vitriol, he said, "that may be free speech, but it may not be without consequences."
Giffords, a 40-year-old centrist Democrat who is a leading proponent of immigration reform and fiscal belt-tightening, had been the subject of at least two "unfortunate incidents" during the recent campaign for reelection to her third term in Congress, Dupnik said. She defeated "tea party" candidate Jesse Kelly by just 4,000 votes.
Much of the public debate over the shooting centered on frequent images of guns in Kelly's campaign. In June, he invited supporters to join him in firing an automatic weapon, to "Get on Target for Victory" and "Help remove Gabrielle Giffords from office."
Dupnik said in one threat against Giffords, someone "in a very angry audience" had a weapon drop out of his pants; in another, the windows were broken at her headquarters. On Saturday, he said, police were investigating a suspicious package found near her Tucson headquarters.
The suspect, said the sheriff, has a "troubled" background and a record of contacts with police. He described Loughner as possibly "unbalanced.... There's reasons to believe that this individual may have a mental issue," he said.
"We're not convinced that he acted alone," Dupnik said. "There's some reason to believe that he came to this location with another individual, and there's reason to believe that the other individual may somehow be involved."
Authorities have a possible photograph of the second person of interest, identified as a white man in his 50s, and are trying to identify him, Dupnik said.
There was no immediate indication that Loughner had overt political connections. A rambling series of YouTube videos posted as "my final thoughts" by someone with the same name talked of "a mind controller ÃƒÂ‚Ã‚Â… able to control every belief and religion."