Jared Lee Loughner (Jail photo)

TUCSON, Ariz. (August 7, 2012)--Jared Lee Loughner, 23, pleaded guilty Tuesday afternoon to charges stemming from a rampage in 2011 in Tucson, Ariz., that left six dead 13 others including former U.S. Rep. Gabrielle Giffords, D-Ariz., injured.

Loughner's plea Tuesday allows him to avoid the death penalty in the January 2011 mass shooting that gained worldwide attention because his intended target was the congresswoman.

Among the dead were Arizona's chief federal judge and one of Giffords' aides.

Federal Judge Larry A. Burns earlier found that Loughner was mentally unfit to stand trial, but ruled Tuesday that months of forcibly medicating him to treat his schizophrenia made him competent to understand the gravity of the charges against him and assist in his own defense.

Loughner listened calmly and without expression while a court-appointed psychologist told the judge he was competent to plead guilty.

Loughner's arms were crossed over his stomach, and he looked straight at Christina Pietz as she testified for an hour.

At one point he smiled and nodded when psychologist mentioned he had a special bond with one of the prison guards.

The college dropout will likely be sentenced to life in prison without parole.