Updated at 6:05 p.m. ET
The FBI and the Pima County Sheriff's Office have finished their investigations into the mass shooting in Tucson that killed six people and wounded 13, including Congresswoman Gabrielle Giffords, spokesmen for the two agencies said Wednesday.
Sheriff's spokesman Jason Ogan said his agency's case was turned over to the FBI, although he did not know when. FBI spokesman Manuel Johnson said all materials have been turned over to the U.S. Attorney's Office for prosecution.
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Investigators interviewed witnesses and survivors of the Jan. 9 shooting outside a Tucson grocery store that killed a 9-year-old girl and a federal judge, among others. They've also interviewed parents, friends and others who know 22-year-old Jared Loughner, who is accused of carrying out the shooting.
Investigators combed through Loughner's home, where he lived with his parents, and seized his property, including a computer and handwritten notes found in a safe that read "I planned ahead," "My assassination" and "Giffords." One note said "Die, bitch," which authorities believe was a reference to Giffords.
Prosecutors say an expert will need a sample of Loughner's handwriting to determine if he wrote the documents.
Loughner will be tried first in federal court before any prosecution begins on state charges.
Loughner pleaded not guilty to federal charges of trying to assassinate Giffords and kill two of her aides. The indictment specifying those charges superseded an earlier federal complaint that also charged him with murder for the deaths of U.S. District Judge John Roll and Giffords aide Gabe Zimmerman.
Another indictment is expected to restore those murder charges.
Loughner's next court hearing is set for March 9.
Meanwhile, Giffords spoke for the first time since she was shot in the forehead, her spokesman said Wednesday, yet another significant milestone in her recovery from a traumatic brain injury.
Giffords first spoke within the past few days and is speaking "more and more," spokesman C.J. Karamargin said Wednesday. He didn't know what her first words were, but said that at breakfast one morning she asked for toast.
"She's working very hard and it's paying off," he told The Associated Press. "We're elated at this. We always knew Gabby is a fighter and that she's not going to let this thing win. And you know, every day is proof of that."
Other news organizations, including Politico, earlier reported that Giffords had asked for toast and was able to speak.
In a Facebook post on Tuesday, Giffords' husband Mark Kelly said his wife had her appetite back and was eating three times a day, "even though it's hospital food."
"It is hard to believe that only one month has passed since Gabrielle was shot," he wrote. "The doctors say she is recovering at lightning speed considering her injury but they aren't kidding when they say this is a marathon process."
He said "there are encouraging signs every day," pointing to her renewed appetite.
"Your prayers are being heard, so don't stop," he wrote.
Kelly, a NASA astronaut, said last week that he expects his wife to be well enough to be at his space launch in two months.
The space shuttle Endeavour will leave April 19 for a two-week mission to the International Space Station, and Kelly will be on board leading a veteran, all-male crew. The mission will be Endeavour's final flight and Kelly's fourth.
Dr. Gerard Francisco, who is treating Giffords at a rehabilitation facility in Houston, said Tuesday that he hopes the congresswoman can make enough progress to attend the space launch, but said it's too early to say.
Arizona state Sen. Ken Cheuvront, a friend of Giffords who shared a house with her and another lawmaker when they served together in the Legislature, said he was excited to hear that she is speaking again.
"It gives all of us a lot of hope that she'll have a full recovery," Cheuvront said. "She's a fighter, there's no ifs, and or butts about that. She's always been very tenacious, and I have no doubt whether it's politics or her recovery that she'll still have that same amount of energy."