A witness to last night's movie massacre says the sight of a small girl who had been shot in the back will stay with him for the "rest of my life".
James Cameron was in the Century Aurora theatre when the shooting began. While others reported that the gunman said nothing, Mr Cameron thought the man was screaming something.
"There was just this loud male scream. It was constant."
Mr Cameron believed there were multiple guns going off and watched in horror as people ran screaming, ducking and trying to escape the gunfire.
He told Fox News: "A child was struck - a little baby girl was struck in the back. That will be something that will stay with me for the rest of my life."
Another theatre-goer, writing online, said she and her boyfriend thought the gunfire was part of the special effects.
"The shooting began during a gunfight scene in the movie, and at first we thought it was special effects when smoke rose up. When shots happened again and people began to run, we thought something was up.
"A guy ran in and shouted there was a gunman in the building, and the alarms to emergency evacuate started to go off.
"I now know what tear gas feels like. I've never had to 'get down' with a police officer screaming at us.
"This is the most f***ed up night of my short life."
A witness identified only as Pam said the gunman came into the theatre from a right-hand exit near the front row.
She said she was pretty sure he was wearing a mask. "He fired a canister into the air - it could have been a smoke bomb or tear gas," Pam said.
"It shot it right into the air, then I started to hear the bang, bang, bang of a gun. I crawled my way through the row. Luckily the exit was close to where I was sitting so I got out pretty fast. I heard more shots as I left."
Salina Jordan, 19, was in Theatre 8 and saw people shot there. She said one girl was struck in the cheek, others in the stomach, including a girl who looked to be aged about 9.
Ms Jordan said it sounded like firecrackers until someone ran into Theatre 8 yelling, "They're shooting out here!"
The police came running in, telling people to run out. Some police were carrying or dragging bodies, she said.
A witness in the neighbouring cinema described a "mass shooting".
"There are a lot of wounded, a lot dead," the man said. "Some guy in a gas mask tear-gassed Theatre 9. We were in Theatre 8. He just lit it up," the witness added.
Others told of bullets coming through the walls and mayhem as people ran for their lives in the dark, many screaming uncontrollably.
Robert Jones, 28, was in the same theatre as the gunman. "I thought it was pretty much the end of the world."
He stayed flat on the ground until police came into the theatre.
Tammi Stevens said her son, Jacob Stevens, 18, was inside Theatre 9 when the shooting started.
He told her he saw a man walk into the theatre wearing body armour and throw a canister that then emitted gas.
"You let your kids go to a late-night movie ... You never think something like this would happen," Tammi Stevens said.