Five buildings surrounding Holmes' residence were then evacuated, and a remotely controlled Adams County Bomb Squad robot was sent into Holmes' apartment early in the morning of July 21, 2012, just a few hours after the shooting, Orman told ABC News.
The Explosives and Incendiaries the Robot Found Upon Entry:
A closer look from the bomb squad's robot camera also revealed dozens of black spheres with fuses all connected to each other and to pickle jars with liquid and bullets inside of them.
The 16 black spheres contained smokeless powder and gasoline, while pickle jars connected to the spheres were layered with thermite, which creates high-temperature fires, in addition to bullets and napalm.
A few 2-liter soda bottles in the back of the apartment also contained more gasoline.
The Booby Traps Holmes Set Up to Trigger an Explosion:
The first booby trap was a trip-wire made of a fishing line with one end connected to the door jam and the other connected to a thermos, Orman said. The thermos had a bottle of nearly pure glycerin perched precariously on a frying pan that contained the chemical potassium permanganate.
If the glycerin had fallen in, a huge flame would've ignited, "blowing up the whole apartment," Osman said.
He added that Holmes set up a recording with 40 minutes of silence, followed by loud music in what he believed was an attempt to get someone to open the door and set off the trap wire.
Holmes' downstairs neighbor Kaitlyn Fonzi testified in May she was drawn to the apartment around midnight by the music, and though she knocked, no one answered so she left.
Two other booby traps involving remote-controlled pyrotechnic systems were also set up by Holmes, including a button set up inside the apartment and a remote control placed by a dumpster outside next to an RC toy car.
"We believe he hoped someone would hear the boom box, try to play with the car and use a remote control that would actually blow the whole place up," Osman said.
None of the trigger systems were ever initiated, and all the bombs were successfully disarmed.
Holmes was convicted in July on one count of the possession of incendiary devices, in addition to two counts for each of the 12 murders and 70 attempted murders he committed inside the theater. He was sentenced last month to 12 life sentences, plus 3,318 years for his crimes.