PHOENIX, Arizona – A 22-year-old charged with trying to kill a US lawmaker in a shooting spree which left six dead and triggered a wave of soul-searching is due in court Monday, his second appearance before a judge.

Jared Lee Loughner could enter pleas at the court in Phoenix, Arizona, where he first appeared two days after the January 8 attacks in Tucson in which he allegedly tried to assassinate congresswoman Gabrielle Giffords.

A federal grand jury indicted Loughner on Wednesday on three counts of attempted murder -- of Giffords and two of her aides -- although further charges are expected, and he could ultimately face the death penalty.

The six people who died included a nine-year-old girl and an Arizona federal judge, John Roll, whose colleagues in the Phoenix courthouse have been disqualified from hearing the case due to the risk they would not be impartial.

The trial is expected to be overseen by California federal judge Larry Burns, from San Diego, although it remains unclear if it will be held in Arizona -- where emotions are likely to run high -- or elsewhere.

In his first appearance in court on January 10 a Loughner -- whose smiling mug shot showing a shaved head was released by police after his arrest -- did not enter any pleas, and shed no light on his motives for the horrific attack.

Loughner's defense lawyer is San Diego-based Judy Clarke, who represented Unabomber Ted Kaczynski -- an anarchist serving life without parole for a 20-year mail bombing spree -- and 9/11 conspirator Zacarias Moussaoui.

Loughner was detained at the scene of the shooting, which took place at a "Congress on Your Corner" public event outside a Safeway grocery store.

Investigators found documents at his home -- where he lived with his parents -- including an envelop on which were written "Giffords," "My Assassination" and "I planned ahead," as well as what looked like Loughner's signature.

It emerged that he had bought the gun and ammunition used in the attack legally in local stores, and that he had been pulled over for running a red light only a few hours before the shooting, but allowed to go with a warning.

Loughner had also left rambling and mostly semi-coherent messages online ahead of the attacks, suggesting he was angry at government and other authorities.

The attacks triggered a firestorm of debate about the influence of America's fiercely divided political culture.

President Barack Obama visited Tucson on January 13 to attend a memorial for the victims of the attack, urging Americans to heal their poisonous political divisions to honor the schoolgirl killed, Christina Taylor Green.

Giffords, shot in the head at point-blank range, is making a remarkable recovery, doctors say. On Friday she was transferred from Tucson to a hospital in Houston, Texas, to be closer to her family as she begins rehabilitation.