Gabrielle Giffords arrived at the Safeway supermarket on Saturday morning optimistic about the basic act of democracy she was reviving.
"My 1st Congress on Your Corner starts now," she announced on Twitter at 9.58am. "Please stop by to let me know what is on your mind or tweet me later." It was a sunny morning in Tucson, the state's second largest city, population 550,000.
Three days earlier, in Washington, Miss Giffords had been sworn in for a third term as representative for Arizona's eighth district, after victory against the odds in November's midterm elections.
In a red suit, and framed by a US flag, an Arizona flag, and a white banner bearing her name, she set up her stall as voters doing their weekend grocery shopping milled around.
She chatted to a couple about Medicare, the state-subsidised system for elderly Americans.
The 40-year-old had made herself unpopular among conservatives by supporting Barack Obama's overhaul of the infamous US healthcare system.
Last March, her constituency office was vandalised shortly after she voted to approve what opponents call "Obamacare".
At about 10.10am, John Roll, a 63-year-old Arizona federal judge walked over to say hello. Mark Kimble, one of Miss Giffords's aides, was emerging from Safeway, with a coffee.
Then there was mayhem. A young, dark-haired man, in a navy blue sweatshirt and sunglasses approached without a word then shot Miss Giffords through the head with a semi-automatic handgun. Judge Roll was also struck.
"Everyone hit the ground," Mr Kimble said. The man, Jared Loughner (22), began spraying the surrounding group with up to 20 rounds. At 10.11am, the first of many 911 calls was made by an onlooker.
People in bloodied clothes fled towards the shop, others lay helpless on the pavement. Some found themselves trapped between Miss Giffords's stall and a concrete post.
The Congresswoman sat slumped against the shop window, held by Daniel Hernandez, another aide who tied a jacket or towel around her head. It may have saved her life.
Steven Rayle, a doctor, lay on the ground, playing dead. As he looked up, the fleeing gunman was being tackled by an elderly passer-by and another Giffords staff member. Mr Rayle scrambled 10ft or so and held down the man's feet. Others soon piled on top.
As the man attempted to reload, an elderly woman prised the fresh magazine out of his hand. He struggled, saying only "stop". Eventually the man was subdued, and arrested by officers who had arrived within four minutes. (©Daily Telegraph, London)