The Colorado shooting that killed at least 12 people early Friday was carried out by the 24-year-old suspect with "calculation and deliberation," police said Saturday. The motive was still not known.
James Eagen Holmes, the suspect in the Aurora, Colorado-movie theater shooting that killed 12 people and wounded 58, received a high volume of deliveries over the past four months to both his home and work addresses, The Associated Press quoted Aurora Police Chief Daniel Oates as telling reporters Saturday.
"What we're seeing here is evidence of, I think, some calculation and deliberation," Oates said. "We have the evidence of a deliberative process to commit this assault, and we have the evidence of a deliberative process in his mind to attack whoever opened the door of his apartment."
The police chief added that Holmes' booby-trapped apartment was "designed ... to kill." FBI Special agent James Yacone described the environment in the apartment as "extremely dangerous." He said anyone who walked in would have sustained "significant injuries" or been killed.
By Saturday evening, "all hazards" from his apartment had been removed.
Police had earlier said the suspect bought the ammunition used in the attack from Aurora, Denver, and Thornton in Colorado between May 22 and July 6.
Authorities released Saturday the names of the 12 people killed, including that of a six-year-old girl, a young man celebrating his 27th birthday and an aspiring sportscaster who had barely escaped a shooting in a Toronto mall earlier this summer.
At least 26 victims remained in five hospitals Saturday, and nine of them were said to be in critical condition.
Civic, community and religious leaders are organizing a vigil at 6:30 p.m. on Sunday in front of Aurora City Hall. "We can now start the natural process of grieving and healing," Reuters quoted Aurora Mayor Steve Hogan as saying.
Also on Sunday, President Barack Obama is scheduled to visit with victims and their families in Colorado.
Holmes, who was being kept in solitary confinement in Arapahoe County Jail, is scheduled for his first court appearance on Monday morning.
Police say Holmes used a military-style semi-automatic rifle, a shotgun and a pistol to open fire on the unsuspecting theatergoers. He set off two gas-emitting devices before spraying the theater with bullets from an AR-15 rifle, a 12-gauge shotgun and a .40-caliber handgun.
He was arrested soon after the shooting at the Century 16 Theaters that was showing the new Batman movie, "The Dark Night Rises," early Friday. He told police he was the Joker, a reference to one of the most prominent villains in the Batman canon.
Police on Friday ruled out it could be a terror attack. "We are not looking for any other suspects," Oates told reporters. "We are confident that he acted alone, but we will do a thorough investigation to make sure that is the case."
Holmes, a graduate from the University of California, Riverside, was identified as a brilliant neuroscience student who grew up in a church-going family in San Diego, Calif. His mother Arlene is a nurse and his father Robert a software company manager. He enrolled in a neuroscience Ph.D. program at the University of Colorado-Denver last year but quit in June.
A résumé posted on Monster.com shows Holmes worked as a summer intern at the Salk Institute for Biological Studies in La Jolla, Calif., in 2006, and mapped the neurons of Zebra finches and studied the flight muscles of hummingbirds while an undergraduate at UC Riverside. He also worked as a summer camp counselor to underprivileged children at a Jewish camp in Los Angeles, Calif., in 2008.