Updated 2:20 p.m. ET
A 22-year-old man described as a social outcast with wild beliefs steeped in mistrust faces a federal court hearing on charges he tried to assassinate Rep. Gabrielle Giffords in a Tucson shooting rampage that left six people dead.
Public defenders are asking that the attorney who defended Oklahoma City bombing conspirator Timothy McVeigh and "Unabomber" Ted Kaczynski defend Jared Loughner, who makes his first court appearance Monday at 2 p.m. MST (4 p.m. EST).
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Authorities weren't saying late Sunday where Loughner was being held, and officials were working to appoint an attorney for him. Heather Williams, the first assistant federal public defender in Arizona, said they're asking that San Diego attorney Judy Clarke be appointed.
CBS News Correspondent Bob Orr reports from Washington that there is no indication that anyone, including Loughner's parents, knew of his alleged plans for Saturday's shootings.
The FBI has interviewed a former roommate of Loughner's who said that sometime between Christmas and New Year's the 22-year-old showed him the gun that he had purchased, Orr reports. That made the ex-roommate uncomfortable, but Loughner made no threats and that meeting was not reported to anyone else.
Investigators have found no evidence that Loughner has any connection to any hate or fringe group, Orr reports. The FBI continues to comb through computer files, notebooks and phone records to learn more about him.
Hours before Loughner's hearing was scheduled to begin, a motion was filed with the court for Clarke and at least two others to represent the 22-year-old. The other lawyers are Mark Fleming and Reuben Cahn, executive director of the Federal Defenders of San Diego Inc.
Jon Sands, the federal public defender for Arizona, wrote in the motion that qualified local public defenders either declined to take the case or found conflicts of interest in representing Loughner and therefore must step aside.
"Given the gravity of the charges, the possibility of the death penalty, and our discussions with the U.S. Attorney's office concerning the charges, we believe that death-qualified counsel must be appointed," Sands says in the motion.
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CNN reported that Clarke had been appointed to represent Loughner, but that report could not be immediately confirmed.
Clarke, a former federal public defender in San Diego and Spokane, Wash., is now in private practice in San Diego. She served on teams that defended several notorious criminal suspects, including 9/11 conspirator Zacarias Moussaoui, McVeigh, Kaczynski, Atlanta Olympic bomber Eric Rudolph and Susan Smith, the South Carolina woman who drowned her toddlers in 1994.
Sheriff Clarence Dupnik said Loughnerand told ABC's "Good Morning America" the suspect had said "not a word" to investigators. Dupnik said authorities were all but certain Loughner acted alone, saying "he's a typical troubled individual who's a loner."
The hearing in Phoenix comes just a few hours after President Obama led a shocked and saddened nation in a moment of silence for the victims and their families. Mr. Obama observed the moment of silence at 11 a.m. EST with White House staff on the South Lawn.
As authoritiesagainst Loughner, they alleged he scrawled on an envelope the words "my assassination" and "Giffords" sometime before he took a cab to a shopping center where the congresswoman was meeting with constituents Saturday morning.
A federal judge, a congressional aide and a young girl were among the six people killed, while Giffords and 13 others were injured in the bursts of gunfire outside a Tucson supermarket.
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. More charges are expected.
The counts involving the murder of federal employees, while on duty,.
Discoveries at Loughner's home in southern Arizona, where he lived with his parents in a middle-class neighborhood lined with desert landscaping and palm trees, have provided few answers to what motivated him.
Court papers filed with the charges said he had previous contact with Giffords. The documents said he hadfrom the Democratic lawmaker in which she thanked him for attending a "Congress on your Corner" event at a mall in Tucson in 2007.
Investigators carrying out a search warrant at his parents' home in a middle-class neighborhood found an envelope in a safe with the words "," "My assassination" and the name "Giffords" next to what appears to be his signature.
Neighbors said Loughner kept to himself and was often seen walking his dog, almost always wearing a hooded sweat shirt and listening to his iPod.
Comments from friends and former classmates bolstered by Loughner's own Internet postings have painted a picture of a social outcast with almost indecipherable beliefs steeped in mistrust and paranoia.
One defense attorney said that if he were representing Loughner he would ask for the trial to be moved out of Tucson.
"You do not want to be in the same venue where someone killed ... a judge and a 9-year-old who was born on 9/11, for heaven's sake," Phoenix defense attorney Adrian Fontes told the Arizona Republic.