After nearly two days of meticulous work, authorities in Aurora, Colorado, said on late Saturday that they had removed all the hazards from the booby-trapped apartment of "The Dark Knight Rises" shooting suspect James Holmes.

Using a robot to set off controlled detonations intended to clear the dangers while still preserving any potential evidence, bomb technicians worked their way through a series of deadly traps that authorities said were intended to kill or seriously injure first responders.

While the initial tripwire in the apartment was designed to kill whoever first opened the door, as authorities slowly moved their way through the nest of threats they found other deadly devices. Among them: artillery shells that shoot out skin-shredding shrapnel, improvised incendiary devices that included a kind of homemade napalm and other accelerants in bottles that would have destroyed the apartment and possibly killed others in the building.

In another sign that Holmes intended to cause as much harm as possible, authorities determined that the 24-year-old suspect in one of the worst mass shootings in U.S. history may have tried to lure his unsuspecting neighbors into the apartment during the shooting spree while leaving loud dance music on and the door unlocked.

A neighbor who lives directly below Holmes told ABC News that she heard the thumping music around midnight, describing it as the "same techno song that sounded like it included gunshots" playing on a loop for a long time. Police believe the music was set up with a timer to begin playing as Holmes made his way to the theater.

Kaitlyn Fonzi said she knocked on the door of the 800-square foot apartment and when no one answered she put her hand on the knob and was about to enter, but had second thoughts. Then, without warning, she said the music stopped around 1 a.m. Among the few details to emerge so far about the contents of Holmes' rigged dwelling: the windows were blacked out with plastic to prevent anyone from seeing inside and a promotional poster for a DVD entitled "Soldiers of Misfortune" hung on a closet depicting several figures, some wearing masks, playing paintball. Holmes wore a gas mask and a type of full-body armor, as well as a helmet, during the assault.

With indications that Holmes planned the attack that killed 12 and wounded 58 others for months, investigators moved with caution to avoid destroying any valuable evidence left behind, including laptop computers or recipes for the improvised explosives in the apartment. In fact, when authorities issued the all clear at 8 p.m. on Saturday, police were seen leaving with a laptop and a hard drive. In all, bomb technicians disarmed more than 30 devices and 30 aerial shells by Saturday night.

Federal law enforcement officials said that the semi-automatic AR-15 rifle Holmes used may have jammed during attack. According to the Associated Press, an official said that the assault rifle with a high-capacity ammunition magazine appears to have locked up, forcing suspect Holmes to switch to another weapon. A 100-round drum magazine, capable of firing 50-60 founds per minute, was recovered at the scene, along with two Glock handguns and a shotgun.

The city of Aurora will hold a [article id="1690156"]prayer vigil[/article] at 8:30 p.m. EST on Sunday night for victims, families and the community where the city's mayor and Colorado's governor are expected to speak. [article id="1690080"]President Obama[/article] will travel to Aurora on Sunday for several hours to comfort the families of those killed in the incident and meet with local authorities. "We need to embrace them and let them know we will be there for them as a nation," the president said Saturday in his weekly radio and Internet address.

Holmes has not been formally charged yet, but will make his first court appearance on Monday morning. He is being held in solitary confinement away from other prisoners on suicide watch and has reportedly refused to cooperate with investigators. Officials have not yet determined a motive in the case.

Described by those who know him as a gifted scientist, former camp counselor for underprivileged children and honors student in high school, the image emerging of Holmes is that of an enigma. Those who knew him say he was a loner who was rarely seen in the company of others in his mostly working-class Hispanic neighborhood in Aurora, yet details have emerged of a profile recently posted on an adult dating website. And, strangely for a young scientist from the Internet generation who appears to have spent months ordering tactical gear and thousands of rounds of ammunition online, he had little or no web presence.

"Dark Knight" star [article id="1690159"]Christian Bale[/article], issued a statement on Saturday to the victims and their families. "Words cannot express the horror that I feel," he said. "I cannot begin to truly understand the pain and grief of the victims and their loved ones, but my heart goes out to them."

After preparing for what some had predicted could be the biggest opening weekend in history, the distributor of the movie, Warner Bros., announced that it would withhold its box-office numbers for the weekend out of respect for the victims. In a rare display of solidarity, Sony, Fox, Disney, Universal and Lionsgate studios said they would also hold back the weekend numbers until Monday.