He got fired from a clothing store and thrown out of college, shaved his head and got tattoos of bullets on his shoulder. He showed up at the apartment of a boyhood friend with a Glock 9-mm pistol, saying he needed it for "home protection." He made dark comments about the government, and, according to one acquaintance, seemed suicidal.
His spiral into madness hit bottom on Jan. 8, 2011. He broke down in tears when a wildlife agent pulled him over for a traffic stop. He went to a gas station and asked the clerk to call a cab as he paced nervously around the store. Gazing up at the clock, he said, "Nine twenty-five. I still got time." About 45 minutes later, Giffords lay bleeding on the sidewalk, along with 11 others who were wounded. Six people were dead.
The information about Loughner's mental state -- and the fact no one did much to get him help -- emerged as a key theme in roughly 2,700 pages of investigative papers released yesterday. Still, there was nothing to indicate exactly why he targeted Giffords.
The files also provided a glimpse at Loughner's parents, who were dealing with a son who had grown nearly impossible to communicate with.
"I tried to talk to him. But you can't. He wouldn't let you," his father, Randy Loughner, told police. "Lost, lost and just didn't want to communicate with me no more."
His mother, Amy Loughner, recalled hearing her son alone in his room "having conversations" as if someone else were there.
Despite recommendations from officials at Pima Community College, which expelled Loughner, that he undergo a mental evaluation, his parents never followed up.
Giffords, in a statement, said that "no one piece of legislation" would have prevented the Tucson shooting, but universal background checks would make communities safer.
Loughner's guilty plea enabled him to avoid the death penalty. He is serving his sentence at a federal prison medical facility in Springfield, Mo.