(CBS News) TUCSON - It was the picture that once you saw it, you couldn't forget it: Jared Lee Loughner, the 23-year-old college drop-out who gravely wounded Congresswoman Gabby Giffords in an inexplicable shooting spree last year that left six dead and 13 wounded.
A federal judge in Arizona ruled Tuesday that Jared Loughner was competent to stand trial, and allowed him to plead guilty> He will spend the rest of his life behind bars.
Federal Judge Larry Burns, who has presided over Loughner's case from the beginning, said he saw a different Jared Loughner on Tuesday.
Loughner, who shouted and ranted at a hearing last year, was quiet and subdued. He spoke in a slurred but understandable voice.
For most of the two-hour hearing Loughner sat calmly by his lawyer's side as his court-appointed psychiatrist described his slow descent into schizophrenia. He smiled just once when she mentioned the name of his favorite prison guard.
Over the past year, Loughner has undergone intensive treatment drugs and counseling. Tuesday, Judge Burns said, "In my mind he knows what's going on. The court finds him competent as of today."
When Burns asked Loughner if he knew what he was doing, he answered distinctly, "Yes, I do." He then plead guilty to 19 counts of murder and attempted murder for this January 2011 Tucson shooting that left six dead and 13 wounded, including Congresswoman Giffords.
To each count Loughner answered, "I plead guilty."
In exchange for his plea, federal prosecutors agreed not to seek the death penalty.
"He's going to be spending the remainder of his natural born life in prison," said U.S. Attorney John S. Leonardo.
Ron Barber, a congressional aide to Giffords who was shot that day, said he approved of the decision.
"My hope is that what happened today in this court can help all of us move forward and continue healing," he said outside the courthouse. "I believe justice was done today."
Suzie Heilman also was shot as she accompanied 9-year old Christina Taylor-Green that day. Taylor-Green was killed.
This makes me proud to be an American," she said. "It's not perfect, we can't have a perfect solution, but this was the best."
Former Congresswoman Giffords and her husbandsaying they are satisfied with the plea agreement. Avoiding trial, they say, will allow them and Arizona to move on.