Arizona shooter could face death penalty

Ms Giffords, who was shot directly in the head at close range, remains in intensive care and on a ventilator, but her doctors said she was responding to verbal commands and showing movement in her fingers and toes.

Neurosurgeon Dr Michael Lemole said: "We're not out of the woods yet.

“Every day that goes by and we don't see an increase [in swelling on her brain], we're slightly more optimistic."

But he added: “It could go either way."

Mr Loughner is also facing two charges for killing a federal government employee and another for attempting to kill a federal employee. Described by those who know him as a loner, he is being defended by Judy Clarke, formerly the lawyer for the "Unabomber" Ted Kaczynski.

A rumour swirling online, prompted by a comment by a friend of Mr Loughner’s in an interview with the political website Mother Jones, suggests that his mother Amy Totman is Jewish.

But there have also been suggestions, including in a Department of Homeland Security memo, that Mr Loughner has links to an extremist and antisemitic organisation called American Renaissance.

Ms Giffords, an up-and-coming name in the Democratic Party and the state’s first Jewish representative, has been a vocal opponent of tightening immigration laws and during her re-election run last year was the subject of a heated Tea Party campaign to oust her.