"I thought it was showmanship. I didn't think it was real," she said.
Seeger said she was in the second row, about four feet from the gunman, when he pointed a gun at her face. At first, "I was just a deer in headlights. I didn't know what to do," she said. Then she ducked to the ground as the gunman shot people seated behind her.
She said she began crawling toward an exit when she saw a girl about 14 years old "lying lifeless on the stairs." She saw a man with a bullet wound in his back and tried to check his pulse, but "I had to go. I was going to get shot."
Then the man began firing, starting with a shot toward the ceiling.
Witness Shayla Roeder said she saw a young teenage girl on the ground bleeding outside the theater. "She just had this horrible look in her eyes .... We made eye contact and I could tell she was not all right," Roeder said.
Police, ambulances and emergency crews swarmed on the scene after frantic calls started flooding the 911 switchboard, officials said. Officers came running in and telling people to leave the theater, Salina Jordan told the Denver Post. She said some police were carrying and dragging bodies.
Hayden Miller told KUSA-TV that he heard several shots. "Like little explosions going on and shortly after that we heard people screaming," he told the station. Hayden said at first he thought it was part of a louder movie next door. But then he saw "people hunched over leaving theater."
Officers later found the gunman near a car behind the theater.
"A gas mask, rifle, handgun (and) at least one additional weapon (were) found inside," Aurora police Chief Dan Oates said, adding that there was no evidence of any other attackers. The suspect spoke of "possible explosives in his residence. We are dealing with that potential threat," Oates said.
A large truck lettered "bomb squad" arrived near an Aurora apartment complex where the suspect is believed to have lived, about four miles from the theater. Dozens of police squad cars, vans and other vehicles were already at the scene, along with black-clad officers carrying automatic weapons.
Police evacuated residents of the building. Oates did not say whether any explosives had been found. He said police also checked for explosives in the parking lot and at the Century 16 theater and secured those areas.
At least 24 people were being treated at Denver area hospitals.
"Warner Bros. and the filmmakers are deeply saddened to learn about this shocking incident. We extend our sincere sympathies to the families and loved ones of the victims at this tragic time," the studio said.
The youngest victim reported was a 6-year-old being treated at Children's Hospital Colorado, where a total of six victims were taken. Their condition wasn't known. Two people in critical condition were rushed to nearby Swedish Medical Center, a spokeswoman said.