Arizona Congresswoman Gabrielle Giffords was clinging to life after a gunman shot her in the head in front of an Arizona grocery store where she was holding a public event, and authorities believe he may have had help.

Pima County Sheriff Clarence Dupnik said tonight investigators are “not convinced” alleged gunman Jared Lee Loughner acted alone when the 22-year-old shot Giffords and and killed six others outside a Tucson Safeway this morning.

Dupnik says officials believe a suspect in custody may have come to the grocery store parking lot with another person, and that person was in some way involved, but he would not elaborate.

Giffords underwent surgery at University Medical Center, and her neurosurgeon was optimistic that she’d recover.

“She was shot in the head, through and through,” surgeon Peter Rhee said. “She was shot one time. It went through her brain. I am as optimistic as it gets in these situations.”

The three-term Democrat, who might have been shot at point blank range, was airlifted to University Medical Center in Tuscon where she was undergoing surgery, Reuters reported.

The cold blooded triggerman randomly fired at the crowd and killed a 9-year-old, a federal judge, a staffer of Giffords’ and three others.

The congresswoman’s father Spencer Gifford, 75, was rushing to the hospital when asked if his 40-year-old daughter had any enemies.

“Yeah,” he told The Post. “The whole Tea Party.”

He added that politicians constantly faced danger.

“They always get threat[ened],” Gifford said, sobbing. “We don’t really have any information. The police department was supposed to call us but they didn’t.”

Ariz. State Sen. Linda Lopez described grave injuries to Fox News.

“She is responding to commands. They feel confident she will make it through surgery,” she said. “Bullets entered one of her temples and exited on the other side of her head.”

Newly elected House Speaker John Boehner said he was horrified by the shooting.

“An attack on one who serves is an attack on all who serve. Acts and threats of violence against public officials have no place in our society,” Boehner said. “Our prayers are with Congresswoman Giffords, her staff, all who were injured, and their families. This is a sad day for our country.”

The congresswoman was chatting up a couple while sitting behind a table during her first “Congress in Your Corner” event at the Tuscon Safeway when the maniacal gunman stalked up to her and pulled the trigger, a witness said.

The gunmen then sprayed a fusillade of bullets into the crowd, who had come out to the informal meeting with the representative.

Giffords had excitedly promoted her event on Twitter.

“My 1st Congress on Your Corner starts now,” she wrote. “Please stop by to let me know what is on your mind or tweet me later.”

Loughner, the gun-toting event crasher, was tackled by a bystander and was taken into police custody, reports said.

The 40-year-old representative, who held her seat since 2007, held strong positions on immigration – a Arizona flashpoint issue.

It is still unclear what motivated the triggerman.

Like many other democrats, Giffords was threatened after the passage of health care reform in March, when the door to her Tuscon office had been smashed.The congresswoman, who held her seat since 2007, was married to U.S. astronaut Mark Kelly.

Watch Loughner’s bizarre YouTube messages:

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