News of Friday's horrific shooting spree in a US movie theater spread quickly on social media, and video and pictures from the scene spread around the world within minutes of the deadly attack.
Within minutes, some on the scene began tweeting about the attack.
Isaac J Ramos wrote: "There was a shooting at century 16 aurora about 30 minutes into the movie. Its crazy."
Domnick Bivins tweeted: "Woww Someone Just Shot Up This Batman Movie. . I Literally Just Seen A Little Girl Get Carried Out With Bullet Wounds Smh The Nerve Of Ppl."
A cameraphone video circulated on YouTube (http://www.youtube.com/watch?v=kx31jI5YnBo) with grainy images of the scene.
And an unidentified victim who apparently survived after being wounded posted a picture of his wound and T-shirt with a hole in it on the file-sharing site imgur (http://imgur.com/a/vtMhj).
Later, some expressed horror, and others said they were just glad to be alive.
"Movie theater just got shot up while we were watching Batman. I'm ok a little freaked out. Walking to Isaac's house with a group of friends," tweeted Jaime Marshall.
One of those killed was Jessica Ghawi, an aspiring sportswriter who recently moved to Denver and who escaped a shooting spree earlier this year in Toronto, according to KENS-TV, quoting family members.
"My friend Jessica Ghawi was killed in the Aurora Shooting -- she was an aspiring sportscaster -- she will be missed," tweeted Natalie Tejeda.
"Just upset, angry, confused. So many lives, so many futures."
Ghawi, who wrote a hockey blog under the name Jessica Redfield, had commented about the Toronto shooting in a June 5 blog post.
"This empty, almost sickening feeling won't go away," she wrote.
"An odd feeling which led me to go outside and unknowingly out of harm's way. It's hard for me to wrap my mind around how a weird feeling saved me from being in the middle of a deadly shooting."
Mourning Ghawi, Jesse Spector tweeted: "Words are useless. Guns more so. If you ever had any interaction with @JessicaRedfield, you know the world is much worse off without her."
Another Twitter member scotia626, wrote: "The Aurora shooter was under the influence of the domestic terror group known as the NRA," a reference to the National Rifle Association pro-gun lobby.
"As a mom, I keep thinking, 'My kids go to the movies all the time.' Heartbreaking, gut-wrenching, senseless tragedy," tweeted Debbie Wasserman Schultz, a Florida congresswoman.
On Tumblr, a member using the name "becsyy" wrote: "R.I.P. all those who lost their lives in the Aurora DKR premiere shooting. It absolutely sickens me that someone could do this to other human beings.
"My thoughts and prayers are with the loved ones of those who have passed or are injured.
The gunman was wearing a gas mask when he opened fire in a crowded US movie theater screening the latest Batman film early Friday, killing at least 12 and wounding nearly 40, police and reports said.
Witnesses described a scene of chaos at the midnight debut showing of The Dark Knight Rises, saying the gunman had set off tear gas bombs and opened fire in the packed theater in Aurora, a suburb of Denver, Colorado.
The shooter was identified by US media as 24-year-old James Holmes.