(CNN)-- President Barack Obama arrived Sunday in Colorado where he began meeting with local officials and families of those gunned down inside a crowded movie theater last week.
Air Force One landed at Buckley Air Force Base in Aurora, Colorado, where he is expected to stay for a two-and-a-half-hour visit. He headed straight to the University of Colorado Hospital, one of several area medical centers that received shooting victims.
Obama will not attend a community prayer vigil, which is scheduled in Aurora Sunday night. He will be briefed on the investigation, officials said,and is expected to address the public before he leaves Colorado.
The man accused of opening fire inside the theater left a trail of evidence that police say suggests the rampage was part of a calculated plan that included killing anyone who tried to learn more about him in the aftermath of the attack.
Authorities have said little about what they believe was the motive of suspect James E. Holmes, though investigators say there is evidence planning was under way for up to two months beforehand.
Twelve people were killed and 58 were wounded in the Friday morning attack that has shocked the nation and reignited a conversation about gun laws in America.
Holmes, 24, is being held in connection with the shootings at the theater and the subsequent discovery of his booby-trapped apartment, which authorities believe he rigged before leaving for the Century Aurora 16 multiplex.
Holmes received a high volume of deliveries over the past four months to both his home and work addresses, which police believe begins to explain how he got his hands on some of the materials used in the attack and those found at his apartment, said Aurora Police Chief Daniel Oates.
"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."
Colorado Gov. John Hickenlooper told CNN's "State of the Union" Sunday he spent a day going from hospital to hospital, talking with survivors.
He concluded that Holmes was a person who wanted to terrorize and instill fear in people's lives, but said he can't conceive of a motive.
"This is a deeply troubled, twisted, delusional person," he said.
One survivor, Josh Nowlan, sustained gunshot wounds, but said he is happy just to be alive. He wouldn't be, he said, if the suspect's gun had not jammed.
"I know I wouldn't be here. If that gun did not jam, I am full certain that I probably would not be here," he said from his hospital bed Saturday.
Police gained access Saturday to Holmes' apartment after intentionally detonating two rigged explosives.
Technicians, with the help of a robot, worked to handle traps, wires and possible explosive and incendiary devices, Jim Yacone, a special agent with the FBI, told reporters Saturday.
The operation proceeded with an eye toward preserving evidence, all of which will be sent to an FBI lab in Quantico, Virginia, Yacone said.
Hundreds of residents were evacuated from five buildings, including the modest, three-story brick building where Holmes told police he had rigged his top-floor, one-bedroom apartment with explosives. All occupants except those who live in the suspect's building were allowed to return home Saturday night.
While the threat to the apartment building Holmes lived was eliminated Saturday, Oates said the residents were being kept out at least until Sunday as investigators work "to preserve evidence."
As of Sunday, at least 17 people remained hospitalized -- eight in critical condition -- in five area hospitals.
Aurora's residents, meanwhile, were grappling with the aftermath of the carnage.
Oates said the Century 16 multiplex would remain shuttered at least until Wednesday to give police time to complete the investigation inside and allow the suspect's defense team access by Tuesday.
Holmes, who is being held in the Arapahoe County Jail, is scheduled to appear in court on Monday morning. The court file was sealed, according to a court order.
Witnesses described the gunman as wearing a gas mask that concealed much of his face and head. He opened fire during a screening of the new Batman movie, "The Dark Knight Rises."
Holmes' hair was dyed red, and he told police when he was arrested in the rear parking lot of the theater minutes after the rampage that he was "the Joker," according to a federal law enforcement source with knowledge of the investigation. The source was not authorized to release details to the media.
The Joker has long been a fixture in Batman comics and was famously portrayed by Heath Ledger in 2008's "The Dark Knight," the predecessor to "The Dark Knight Rises."
Oates has declined to release details about Holmes' appearance other than to describe what he was wearing: a ballistic helmet and protective gear for his legs, throat and groin, black gloves and a gas mask.
He also said he would not release the booking photo "for investigative reasons."