A 22-year-old man has appeared in court in Phoenix, Arizona to face charges that he attempted to assassinate US Representative Gabrielle Giffords and murdered US District Judge John Roll in a shooting spree that claimed six lives and wounded at least 13 others.
Jared Lee Loughner was returned to federal custody after today's hearing without entering a plea.
Loughner has been charged with two counts of first-degree murder, one count of attempted assassination of a member of Congress and two other counts of attempted murder.
Attacks on federal officials are considered federal crimes. When reading the charges, judge Anderson paused dramatically after the name of his slain colleague, Arizona's chief district judge, John Roll.
He is also accused of killing Gabriel Zimmerman, a member of Giffords's staff, during the January 8th rampage at a Tucson, Arizona, shopping mall, according to a criminal complaint filed yesterday.
He is also charged with attempting to kill two other members of Giffords's staff.
Federal prosecutors said they are drafting an indictment against Loughner for presentation to the grand jury.
Loughner will next appear in court for a preliminary hearing on January 24.
Investigators found an envelope with Giffords' name, along with the words "I planned ahead" and "my assassination" in a safe in Loughner's home.
The safe also contained a letter to "Jared Loughney (sic)", signed by Giffords, in which she thanked him for attending a rally at a mall in Tucson in August 2007.
Meanwhile, doctors are optimistic that Ms Giffords will recover after being shot in the head, but she is still in critical condition in a Tucson hospital following emergency brain surgery.
The shooting spree in Tucson on Saturday has fuelled debate about extreme political rhetoric in the United States after an acrimonious campaign for congressional elections in November.
The US government has charged the suspected shooter, Jared Lee Loughner, with two counts of first-degree murder, one count of attempted assassination of a member of Congress and two other counts of attempted murder.
President Barack Obama and his wife Michelle led Americans in observing a moment of silence today to commemorate the victims of the shooting.
FBI director Robert Mueller cautioned public officials to be on alert, but said there was no information to suggest a further specific threat.
Mr Mueller said "hate speech and other inciteful speech" presented a challenge to law enforcement officials, especially when it resulted in "lone wolves" undertaking attacks.
"When the rhetoric about hatred, about mistrust of government, about paranoia of how government operates, and to try to inflame the public on a daily basis, 24 hours a day, seven days a week, has impact on people especially who are unbalanced personalities to begin with," said Clarence Dupnik, the sheriff of Pima County where the shootings occurred.
Additional reporting: Agencies