The man accused of shooting dead 12 people in a Colorado cinema made his first appearance in court today.
Formal charges against James Eagan Holmes, 24, will be filed on 30 July, the judge presiding over the proceeding said.
A public defender was appointed as his attorney.
Police say Mr Holmes was dressed in body armour and carrying three guns when he opened fire at a packed midnight screening of the new Batman movie on Friday.
The attack left 12 people dead and another 58 wounded.
Mr Holmes was apprehended moments after the shooting.
Police are still searching for a motive for the crime.
On a live television broadcast of the proceedings, Mr Holmes could be seen sitting silently, looking straight ahead, occasionally closing his eyes.
US President Barack Obama travelled to Aurora, a Denver suburb of 325,000, to offer comfort to families of the victims.
He told them their loved ones would be remembered long after the justice system was done with the killer.
The dead included war veterans, an aspiring sportscaster, who had barely escaped a shooting in a Toronto shopping centre earlier this year, and a six-year-old girl.
Former Denver prosecutor Craig Silverman said the crime meets all the elements of Colorado capital case law, including premeditation, multiple victims and the killing a child, among others.
Mr Obama met families in the University of Colorado Hospital.
In a televised address afterwards, he focused on the bravery of a young woman, Stephanie Davies, who saved her friend by putting pressure on a gushing neck wound with one hand and calling for help on her mobile phone with the other.
Mr Holmes' motives remain largely a mystery, with past associates saying he displayed no hints of a mental illness or violent tendencies.
He was armed with a Smith & Wesson M&P .223 semi-automatic rifle, similar to an AR-15 assault rifle, a 12-gauge shotgun and a Glock .40-caliber handgun.
Police found an additional Glock .40-caliber handgun in his car.
All the weapons had been bought legally.
He is being held in solitary confinement to protect him from other prisoners.
Mr Holmes had recently dropped out of a doctoral degree programme in neuroscience at the University of Colorado's Anschutz Medical School, a few blocks from his apartment.
Mother's comment was 'misconstrued'
Elsewhere, a lawyer representing the family of Mr Holmes has said his mother's initial comment to ABC News on the morning of the shooting has been misconstrued.
Reading a statement she attributed to Arlene Holmes, San Diego-based lawyer Lisa Damiani said Mrs Holmes' comment "You have the right person" to an ABC reporter referred to herself, not Mr Holmes as some media have suggested.
Mrs Holmes made the comment when the ABC reporter phoned her early on Friday morning and asked if she was Arlene Holmes and if James Holmes was her son, Ms Damiani said.
Her comment has been misconstrued to suggest she was not surprised by her son's alleged involvement in the shooting.
At a press conference outside her office, Ms Damiani said the Holmes family is choosing not to discuss Mr Holmes or his relationship with the family at this time.
She declined to answer questions about the family's whereabouts.
The family are "doing as well as they can under the circumstances," said Ms Damiani.