There are disturbing new photos of James Holmes' booby-trapped apartment

Prosecutors have just released hundreds of disturbing photos of an apartment belonging to James Holmes, who's spending life in prison for killing a dozen people at a midnight premiere of "Batman: The Dark Knight Rises."

Holmes had spent months planning the July 20, 2012 attack at an Aurora, Colorado movie theater that left 12 dead and 70 injured.

He had several high-powered weapons and fired "many, many rounds," according to Police Chief Dan Oates.

Though he had worn body armor during the attack, "He surrendered without any significant incident," Oates said.

Holmes told the police he was "the Joker," the terroristic villain of the Batman franchise. He warned police that his apartment had been booby trapped. At the time Oates described what they found as an "incendiary device," but until now the public hasn't had a full picture of what extremes Holmes went to.

Now that the trial has concluded, and Holmes has been sentenced to life in prison without the possibility of parole, hundreds of photos of the jerry-rigged apartment have been released because of an open records request. Some of these images were used in the trial against him; all of them are shocking and disturbing.

Initially a robot was sent into the apartment to investigate and spray water on the explosives.

Wires were strewn about the apartment linking different explosives. Oates told the Denver Post the devices were "pretty sophisticated," adding that "we could be here for days."

A mixture of bullets, gunpowder, and a flammable liquid are wired to explode in Holmes' apartment.

Among the improvised devices were 30 homemade grenades, pictured below.

Holmes' living room was littered with lighter fluid, containers of gasoline, and gunpowder.

These images are jarring. However, Army veteran Gary Smith, an explosives expert with the Bureau of Alcohol Tobacco Firearms and Explosives, whose team worked to diffuse the many bombs, told NBC that, "I really wasn't too scared."

During the investigation, an unnamed official told CNN that if the devices went off "you would have an explosion that would knock down the wall of (nearby) apartments." He added, "That flame would have consumed the entire third floor."

Authorities say that there were 10 gallons of gasoline in different containers throughout the apartment.

Besides the bombs, the apartment was relatively empty with little furniture. The Batman mask below is one of Holmes' few personal effects left behind.