- Federal prosecutors brought charges against the gunman, Jared Loughner, 22, accused of carrying out an assassination attempt on Congresswoman Gabrielle Giffords and killing six people at a political event in Arizona. Loughner is scheduled to make his initial court appearance Monday in Phoenix.
- A second man considered a person of interest has been cleared of any involvement.
- Giffords is in a medically-induced coma and doctors said it could be months before they know the extent of damage to her brain.
- One of the six killed include 9-year-old Christina Green, the daughter of Los Angeles Dodgers scout John Green and the granddaughter of legendary MLB manager Dallas Green.
- Investigators carrying out a search warrant at Loughner's parents' home found an envelope in a safe with the words "I planned ahead," "My assassination" and the name "Giffords" next to what appears to be Loughner's signature.
Giffords was one of 20 people who were hit when Loughner opened fire at a public gathering outside a busy Tucson supermarket about 10 a.m. Saturday. Five people died at the scene and one died at a hospital.
Pima County Sheriff Clarence Dupnik said the rampage ended only after two people tackled the gunman.
Loughner is in federal custody. A criminal complaint filed in federal court charges Loughner with one count of attempted assassination of a member of Congress, two counts of killing an employee of the United States and two counts of intent to kill employees of the United States.
Loughner reportedly has a history of mental problems. An eyewitness said Loughner looked determined and let loose with a barrage of bullets.
Rep. Giffords' condition
Doctors said Giffords is responding to questions and is able to understand and respond to simple commands. While the slightest bit of brain swelling could make her condition take a turn for the worse, they said they are "cautiously optimistic."
Dr. Michael Lemole said the gunshot went through the left side of her head, and surgeons worked to reduce pressure from swelling in the brain by removing bone fragments.
Giffords graduated from Scripps College in Claremont, and in 2009, she was the commencement speaker.
The president of the school said Giffords spoke about the importance of being authentic, and that taking tough positions and being true to yourself sometimes means you don't always make friends.
Daughter of Dodger scout among the dead
One of the six killed include a 9-year-old girl named Christina Taylor Green, the daughter of Los Angeles Dodgers scout John Green and the granddaughter of legendary Major League Baseball manager Dallas Green.
"She was born on Sept. 11, so she came in on a tragedy, and now she's gone out on a tragedy," John Green said.
Her parents say she was an aspiring politician and had just been elected to student council at her school. She was attending Giffords' meeting with constituents to learn more about the process.
Green told her parents she wanted to attend Penn State and have a career that involved helping those less fortunate than her.
On Sunday, players from the Dodgers spoke about the tragedy and the loss of the team.
"Any time something tragic like that happens it affects us because we are a tight-knit group," said Dodgers catcher Griff Erickson. "We are a family and we're always trying to pull for each other. My heart goes out to (John Green's) family."
The other five that were killed were federal Judge John Roll, 63, Giffords' director of community outreach Gabriel Zimmerman, 30, 76-year-old Dorothy Morris, 76-year-old Dorwin Stoddard and 79-year-old Phyllis Scheck.
Lawmakers not surprised by violence
According to law enforcement officials, members of Congress reported nearly three times the number of cases of threats or violence in the first three months of 2010 than compared to the previous year.
Fellow lawmakers said they are not surprised by the violence because the political rhetoric has gotten out of control. Giffords, a Democrat from a largely Republican district, has received more threats than most lawmakers, and recently, her Tucson office was vandalized after she supported the health care bill.
"Disturbing when you know that you're going out to an environment that some people may not agree with you, but we would hope that it wouldn't resort to someone would feel they have to use force and harm to someone just because they disagree with their acts," said Rep. Laura Richardson of Long Beach.
Congressman Dan Lungren is calling for a re-evaluation of security procedures for U.S. representatives at public events.
"I would recommend very strongly that members of Congress revisit the relationship they have with local law enforcement, and sit down and talk with local law enforcement about what's appropriate in terms of a presence of law enforcement when a member of Congress has a public gathering of some sort," he said.
ABC News and the Associated Press contributed to this report.