A 19-year-old gunman who police said killed eight people and then himself at a Nebraska mall left a suicide note predicting the shootings would make him famous, his landlord said.
Police have identified the gunman as Robert A. Hawkins, 19, of Nebraska.
Five other people were injured, and two of them were in critical condition, hospital officials said.
The shootings inside the Von Maur department store at the popular Westroads Mall in Omaha sent panicked holiday shoppers fleeing for cover.
"It was just so loud, and then it was silence," said witness Jennifer Kramer, who hid behind a clothing rack. "I was scared to death he'd be walking around looking for someone else."
Police identified the gunman as Robert A. Hawkins of Nebraska.
Chief Thomas Warren of the Omaha Police Department called the shooting "premeditated," but said it "appears to be very random and without provocation."
Debora Maruca Kovac, Hawkins' landlord, said she found the suicide note after getting a phone call from Hawkins about 1 p.m., just minutes before the shootings.
"He basically said how sorry he was for everything," Maruca Kovac said of the note. "He didn't want to be a burden to people and that he was a piece of s--- all of his life and that now he'd be famous."
She said Hawkins was a friend of her sons and "reminded me of a lost puppy that nobody wanted." He came to live with her about a year and a half ago, telling her he could not stay with his own family because of "some issues with his stepmother."
She described Hawkins as well-behaved, although "he had a lot of emotional problems, obviously."
The shootings began about 1:42 p.m. (2:42 p.m. ET).
Seven people were found dead at the scene by officers who arrived six minutes later; two others, a male and a female, died after being transported to Creighton University Medical Center, said Fire Chief Robert Dahlquist.
A Creighton spokeswoman said a second female underwent surgery and was in critical condition Wednesday afternoon.
Three other people were taken to the University of Nebraska Medical Center.
One, a 61-year-old man who sustained a chest wound after being shot in the armpit, had surgery and remained in critical condition in the intensive care unit Wednesday night, said hospital spokeswoman Maggie O'Brien.
The other two -- a 34-year-old man who was shot in the arm, and a 55-year-old man who fell and struck a clothing rack as he was trying to escape -- were treated and released, she said.
Warren said Hawkins was armed with an SKS assault rifle. His body, and the weapon, were found on the store's third floor, he said.
Maruca Kovac told CNN that Hawkins left the house Wednesday about 11 a.m., and called the house about two hours later, sounding upset.
"He just said he wanted to thank me for everything I'd done for him ... and he was sorry," Maruca Kovac said. He told her he had gotten fired from his job at a McDonald's restaurant, she said.
"I said, 'Come home and we'll talk about it,' " she recounted. "He said, 'It's too late.' He said he'd left a note explaining everything."
Kramer told CNN she heard at least 25 shots.
"I looked at my mom and said, 'We need to get out of here. Those are gunshots,' " Kramer said. "I just grabbed my mom and we ran to the back of the men's department and hid in some pants racks."
"He just kept firing," he said. She said she called 911 on her cell phone, whispering into it out of fear of being heard. A dispatcher told her other calls had been received and help was on the way, but she said it seemed to take "a long time" for them to arrive.
She said as she was being escorted out by police, she saw a man lying injured by the escalator where she had been previously.
Mall employee Charissa Tatoon said a man by an escalator near her was heard saying he was calling 911.
"Immediately after that, the shooter shot down from the third floor and shot him on the second floor," she said.
"All of us were slightly confused because we didn't know what it was," Tatoon said. "Immediately after that, there was a series of maybe 20 to 25 more shots up on the third floor."
Warren, the police chief, said the victims included five females and three males, not including Hawkins. The shooting appeared to be contained in the Von Maur store, he said.
"We believe there was one shooter, and one shooter only," he said.
Maruca Kovac said she was unaware Hawkins had any guns, although he knew a lot about them, as did his stepfather.
"When he first came to live with us, he was in the fetal position and chewed his fingernails all the time," she said. But she said she thought he was improving, as he had gotten a job, a haircut and a girlfriend.
However, she said Hawkins and his girlfriend had broken up in the last couple of weeks, and he had taken it hard.
She said late Wednesday that authorities were searching her house for evidence.
"My kids are devastated," she said. "We're all in shock."
Hawkins' former school district released a photo of a youth with glasses and long black hair. A spokeswoman said he attended Papillion-La Vista High School until he withdrew in March 2006.
President Bush had visited Omaha Wednesday before the shooting.
"The president is deeply saddened by the shootings in Omaha," White House press secretary Dana Perino said. "His thoughts and prayers are with the victims and their families."
The shooting was at least the fourth at a mall or shopping center so far this year, following incidents in Salt Lake City, Utah; Kansas City, Missouri; and Douglasville, Georgia.