Jared Loughner, 22, was charged with one count of attempted assassination of a member of Congress and four other charges.
Congresswoman Gabrielle Giffords, who was shot in the head in an assassination attempt that killed six others, is able to respond to doctors’ commands, a surgeon said last night.
Dr Michael Lemole, who is treating 40-year-old Ms Giffords in Arizona, told a news conference she is able to communicate.
Outside of the hospital, candles flickered at a makeshift memorial as well-wishers prayed for the congressman’s recovery.
Giffords, a member of President Barack Obama’s Democratic Party, was shot on Saturday as she met with constituents at a Tucson supermarket.
Six others were killed and 14 were wounded.
Dr Lemole said the gunshot went through the left side of her head and surgeons worked to reduce pressure from swelling in the brain by removing bone fragments.
Doctors said they were “very, very encouraged” by Giffords’ ability to respond to simple commands along with their success in controlling her bleeding.
Surgeons said she was able to respond to commands such as squeezing a hand or showing two fingers. They credited several reasons for her survival, including good luck and the fact paramedics got her to surgeons quickly — in under 40 minutes.
The medical prognosis came as authorities investigated the motivation of the gunman.
The gunman also fired at her district director and shot indiscriminately at staffers and others standing in line , said Mark Kimble, a communications staffer for the congresswoman.
“He was not more than three or four feet from the congresswoman and the district director,” Kimble said, describing the scene as “just complete chaos, people screaming, crying”.
One of the victims was nine-year-old Christina Taylor Green, who was a member of the student council at her local school and went to the event because of her interest in government. She is the granddaughter of Dallas Green, the former manager of the Philadelphia Phillies major league baseball team.
She was born on 9/11.
Police said the gunman was in custody, and was identified as Jared Loughner, 22.
His motivation was not immediately known, but Pima County Sheriff Clarence Dupnik described him as mentally unstable and possibly acting with an accomplice.
Sherrif’s Deputy Jason Ogan said last night a second man has been cleared of any involvement in the shooting. The man was a cab driver who drove the gunman to the grocery store. The driver went into the store because the gunman hadn’t paid his fare. Ogan said, “The cab driver came by, and we determined he was not involved.”
He also said authorities were not ready to say if they are confident the gunman acted alone.
The assassination attempt left Americans questioning whether divisive politics had pushed the suspect over the edge.
Giffords faced frequent backlash from the right over her support of healthcare reform last year, and had her office vandalised the day the House of Representatives approved the landmark measure.
Dupnik lashed out at what he called an excessively “vitriolic” atmosphere in the months leading up to the rampage.
The sheriff said the rampage ended only after two people tackled the gunman.
“He was definitely on a mission,” according to event volunteer Alex Villec, a former Giffords intern.
Attorney General Eric Holder said that FBI director Robert Mueller was travelling to Arizona to help co-ordinate the investigation.
In a brief statement House Speaker John Boehner said flags on the House side of the Capitol in Washington will be flown at half staff to honour Giffords’ slain aide, Gabe Zimmerman.
A shaken President Barack Obama called the attack “a tragedy for our entire country”.
The House of Representatives has called off proceedings in Washington for the upcoming week.