WASHINGTON: President Barack Obama will travel to Colorado on Sunday to meet with families bereaved in a shooting rampage that left at least 12 dead and 58 wounded at a movie theater in a Denver suburb.

Obama is due to meet with members of the families of the victims — ranging from six to 51 years of age — who were shot to death in this Denver area suburb when a gunman opened fire on movie goers during a packed premiere of the latest “Batman” film on Friday.

A vigil is scheduled for 6:30 p.m. on Sunday in front of Aurora city hall, organized by civic, community, and religious leaders. “We can now start the natural process of grieving and healing,” Aurora Mayor Steve Hogan said at a memorial late on Saturday for one young shooting victim: “We're still reeling.”

Obama's trip comes as investigators are deepening a probe into the shooter accused of planning the massacre. On Saturday, local and federal authorities disarmed his booby-trapped apartment.

Graduate school dropout James Holmes, 24, was arrested immediately after the fatal spree at the local multiplex. Aurora Police Chief Dan Oates said the shooting followed months of “calculation and deliberation,” as Holmes received a “high volume” of deliveries to both his work and home.

Residents of several nearby buildings were allowed to return home on Saturday, while the red-brick apartment block where Holmes lived remained under evacuation as local and federal authorities completed the painstaking process of disarming the explosives and sifting through evidence.

Sources familiar with the probe said that some 30 shells filled with gunpowder were found in the 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.

On Saturday afternoon, the local coroner's officer released the names of the 12 people killed, including those 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.

The mass shooting stunned the nation, evoking 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. It also reverberated in the US presidential race.

Both President Barack Obama and his Republican rival, Mitt Romney, toned down their campaigns on Friday, pulled ads from Colorado and dedicated scheduled events to the victims.

Those who witnessed the shooting told of a horrific scene, with dazed victims bleeding from bullet wounds, spitting up blood and crying for help.

Holmes, 24, was arrested minutes later in a parking lot behind the cinema. He was armed with an AR-15 assault rifle, a 12-gauge shotgun and a Glock .40-caliber handgun, Oates said.

Police found an additional Glock .40-caliber handgun in his car. All the weapons were legally bought in the past 60 days.

Arapahoe County Sheriff Grayson Robinson said the suspect was being held in solitary confinement to protect him from other prisoners, a routine move in high-profile cases.