Alleged "Batman" theatre gunman James Holmes meticulously planned the 2012 massacre after breaking up with his girlfriend and flunking college, prosecutors have said, giving harrowing details of the slaughter.
In opening remarks at Holmes' trial yesterday, prosecutor George Brauchler gave the first authoritative blow-by-blow account of the killings that left 12 dead and 70 injured in Aurora, Colorado.
"On a cool July night...400 people filed into a box-like theatre to be entertained...And one person came in to slaughter them," the prosecutor said, pointing at Holmes in a hushed courtroom.
The death toll could have been much higher, Brauchler said -- but a gun cartridge jammed in the movie theatre, while booby-trapped explosives he rigged at his apartment failed to go off.
The 27-year-old, who has pleaded not guilty due to insanity, listened calmly as the prosecutor set out his case on the first day of his trial, which could see Holmes face the death sentence.
Holmes -- who sported neatly-trimmed brown hair and a beard for the first court session -- has been in custody since the night of the mass murder in Aurora, Colorado on July 20, 2012.
Grisly and harrowing evidence is being presented at the trial.
In an emergency 911 call from that night, played in court, repeated shots and screams can be heard as a caller tells the police dispatcher about the unfolding massacre.
Brauchler opened his case by showing a photo of the back door of the Aurora movie theatre, smeared with blood.
"Through this door is horror," he said. "Through this door is bullets, blood, brains and bodies."
Witnesses said Holmes -- who had bright orange hair at the time of the attack -- threw smoke bombs before opening fire randomly with weapons including an AR-15 military-style rifle, a 12-gauge shotgun and a .40-calibre pistol.
Prosecutors say Holmes had enough ammunition to kill everyone in the crowded theatre showing "The Dark Knight Rises.
