President Barack Obama on Sunday traveled to Colorado and offered hope and comfort to victims of the gunman who killed 12 people and wounded 58 in a Denver-area movie theater.
The shooting spree early on Friday shocked the nation and dominated the news. Obama met privately with the families of victims and said he had listened to stories about those who were killed and those who risked their lives to help others.
"They assure us that out of this darkness a brighter day is going to come," Obama said at the University of Colorado Hospital in Aurora, Colorado, recounting the story of a young woman who stopped the bleeding of her wounded friend with one hand and called for help on her cell phone with the other.
After justice was done, memory would focus on the victims, not the killer, he said.
Obama said in a televised address after meeting the families that he told them that the nation was watching and shared their grief. He spoke shortly before a memorial service by the community.
"The entire country will be there in prayer and reflection today," he said.
A makeshift memorial sprang up in the town of 325,000, while across the nation on Sunday, people mourned the dead, honored those who shielded others from harm and debated whether gun control could stop such tragedies.
The gunman, identified by police as graduate school dropout James Eagan Holmes, carried an assault rifle, shotgun and handgun into a packed midnight premiere of the Batman film "Dark Knight Rises" on Friday morning.
His spray of bullets took the lives of victims ranging from a 6-year-old girl to a 51-year-old man. Many of the wounded are still in the hospital.
Iraq war veteran Christina Blache said she thought the shots were part of the show. But she was hit and a friend who was celebrating his 27th birthday died. "Who expects to be shot in a movie theater? None of us did," she told CNN.
Josh Nowlan said that he watched the shooter pick off victims - but then his rifle jammed. "If that gun did not jam, I am full certain I would not be here," he told CNN.
"We're still reeling," Aurora Mayor Steve Hogan said at a memorial late on Saturday for one young shooting victim.
A dozen crosses with names of the dead now stand on a small hill across the street from the movie theater. Flowers stood in front of all the crosses and a giant teddy bear was next to one with the name of the youngest killed, 6-year-old Veronica Moser-Sullivan.
A sign reading "7/20 gone not forgotten" was surrounded by balloons, flowers, American flags, Air Force hats and flags, and dozens of hand-written notes.
Holmes and his motives remained largely a mystery on Sunday, with past associates of the 24-year-old saying he displayed no hints of a mental illness or violent tendencies. Police said they had finished collecting evidence from Holmes's booby-trapped apartment but that the building was unsafe because of chemical hazards in his home.
Aurora Police Chief Dan Oates said the shooting was the product of months of "calculation and deliberation," with Holmes receiving a "high volume" of deliveries at work and home.
Area shooting range owner Glenn Rotkovich, 65, was among the few who found Holmes suspicious. Rotkovich said he received an emailed membership application from Holmes about a month ago and heard a "bizarre, freakish message" when he called to contact Holmes.
"It was a very deep voice, a guttural rambling," Rotkovich, owner of the Lead Valley Range, told Reuters. "I couldn't understand it. I didn't try and understand it. That was all I needed to know."
Colorado Governor John Hickenlooper, speaking on NBC television's "Meet the Press" program, said there were still no clues as to the motive for the shooting. But he said Holmes was "a twisted, really delusional individual" who had not been cooperating with authorities.
"He was diabolical, demonic," Hickenlooper said.
On Saturday afternoon, the local coroner's officer released the names of the 12 people killed, including an aspiring sportscaster who had barely escaped a shooting in a Toronto mall earlier this summer.
Those who witnessed the shooting told of a nightmarish scene, with dazed victims bleeding from bullet wounds, spitting up blood and crying for help.
For many, it evoked memories of the 1999 massacre at Columbine High School in Littleton, 17 miles (27 km) from Aurora, where two students opened fire and killed 12 students and a teacher.
The incident has also reverberated in the U.S. presidential race. Both Obama and his Republican rival, Mitt Romney, toned down their campaigns on Friday, pulled ads from Colorado and dedicated scheduled events to the victims.
In Rome on Sunday, Pope Benedict expressed dismay and sadness at the shooting.
"I was deeply shocked by the senseless violence which took place in Aurora, Denver," he said in his regular Sunday Angelus address.
Holmes was arrested in a parking lot behind the cinema. 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 in the previous 60 days.
Arizona Senator John McCain told CNN on Sunday, the one-year anniversary of a mass attack in Norway in which a lone gunman killed dozens, that he needed to be convinced that tighter gun control would solve the problem.
"The killer in Norway was in a country that had very strict gun control laws, and yet he was still able to acquire the necessary means to initiate and carry out a mass slaughter," McCain said.
But California Senator Dianne Feinstein questioned why a clip holding as many as 100 bullets, which police say Holmes bought, was available in the United States. "You don't need it for self-defense. Why do you need it? Why do we make it available?" she said on Fox.
Authorities said Holmes had dyed his hair red and called himself "the Joker" in a reference to Batman's comic-book nemesis.
He is due to make his initial appearance before a judge at the Arapahoe County Justice Center on Monday morning.
Sources familiar with the investigation said some 30 softball-sized containers filled with gunpowder were found in Holmes' apartment, together with containers filled with "incendiary liquids" intended to fuel a fire from the initial explosions, as well as bullets meant to ricochet around the apartment.
Holmes was being held in solitary confinement to protect him from other prisoners, a routine precaution in high-profile cases, said Grayson Robinson, sheriff of Arapahoe County.
Until last month, Holmes was studying for a doctoral degree in neuroscience at the University of Colorado's Anschutz Medical School, a few blocks from his apartment.