Jared Loughner, 22, Monday on federal charges that he tried to assassinate U.S. Rep. Gabrielle Giffords and killed a federal judge. He is also accused of killing five others and wounding or injuring 13 others.
Loughner's parents, Randy and Amy Loughner, are devastated, according to neighbor Wayne Smith, 70.
"And they feel guilty for what happened," he told KPHO-TV Monday evening.
Special Section: Tragedy in Tucson
"They want to know, where did they fail? I told them they didn't fail. They taught him everything about right and wrong. We all know you can teach someone everything and have no control how it works out."
Amy Loughner has been in bed, crying nonstop since Saturday, Smith said. In an interview with the Wall Street Journal, Smith said the pair - who haven't been seen the incident on Saturday - were "hurting real bad … They are devastated."
Roxanne Osler, of Tucson, whose son had been a friend of Jared Loughner's, said he had a bad relationship with his parents and had distanced himself from family.
"What Jared did was wrong. But people need to know about him," she told The Washington Post. "I wish people would have taken a better notice of him and gotten him help. ... He had nobody, and that's not a nice place to be."
Loughner's parents have not spoken publicly, though Smith said the father plans to release a statement.
Apart from Smith, 70, only a team of the Loughner residence since the shooting.
Sources told the Journal that Randy and Amy Loughner expressed a degree of shock in their discussion with the FBI, saying they were unaware of the degree of their son's apparent mental problems.
"They liked their privacy," George Gayan, who has lived next door to the Loughners for three decades, told the newspaper. He said it wasn't unusual to go three or four days without even seeing Randy Loughner.
Neighbors told the Journal they believed Randy had stopped working when Jared was born, and raised him full-time as Amy continued working to support the family.
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According to the report, it was Smith himself who delivered the news to Randy and Amy Loughner that their son was under arrest and suspected of a mass shooting on Saturday. He told the Journal he informed the couple what was going on when they returned to their home after shopping to find it swarmed by police.
Wearing a beige prison jumpsuit and handcuffs and sporting a pink gash on the hairline of his shaved head, Loughner on Monday afternoon spoke just a brief reply when the judge asked if he understood that he could get life in prison - or the death penalty - for killing federal Judge John Roll.
"Yes," he said.
Loughner was being held without bail. Meanwhile, residents of Tucson prepared for memorial services Tuesday for the six killed in the shooting.
The first real community gathering for mourners since the rampage - a Mass for all the victims at St. Odelia's Parish in Tucson - was set for 7 p.m. President Barack Obama was scheduled to arrive in Arizona Wednesday for a memorial service days after calling the attack a tragedy for the entire country.
Loughner's court appearance in Phoenix on Monday gave the nation a first look at the man authorities say is responsible for the shooting that also left 14 injured or wounded outside a Tucson supermarket where Giffords had set up a booth to hear the concerns of constituents.
Giffords, a three-term Democrat, at Tucson's University Medical Center, gravely wounded after being shot through the head but able to give a thumbs-up sign that doctors found as a reason to hope.
With few new details emerging at Monday's hearing, questions remained about what could have motivated someone to arm himself with a pistol and magazines carrying 33 bullets each, and rain gunfire on a supermarket parking lot crowded with men, women and children.
A military official in Washington said the Army rejected Loughner in 2008 because he failed a drug test. The official spoke on condition of anonymity because privacy laws prevent the military from disclosing such information about an individual's application.
The official did not know what type of drug was detected.
Prosecutors say he scrawled on an envelope the words "my assassination" and "Giffords" sometime before he took a cab to the shopping center. Police said he bought the Glock pistol used in the attack at Sportsman's Warehouse in Tucson in November.
The revelation about the shooter's high-capacity magazines led one longtime Senate gun control advocate, Sen. Frank Lautenberg, D-N.J., to announce plans to re-establish a prohibition that lapsed in 2004 on magazines that feed more than 10 rounds at a time.
At his appearance Monday in a Phoenix courtroom, about 100 miles away from where the shooting took place, Loughner seemed impassive and at one point stood at a lectern as a U.S. marshal stood guard nearby.
His newly appointed lawyer, Judy Clarke, who defended "Unabomber" Ted Kaczynski, stood beside him and whispered to him before the judge ordered him held without bail.
Loughner is charged with one count of attempted assassination of a member of Congress, two counts of killing an employee of the federal government and two counts of attempting to kill a federal employee. Those are federal charges.
State prosecutors, meanwhile, are researching whether they have to wait until after the federal case is resolved, or if they can proceed with local charges at the same time, an official said.