Day two of the Aurora shooting trial wasn't quite as heartbreaking as the first, with local police from the movie theater replaced on the witness stand by bombing experts dissecting the suspect's apartment. But Tuesday's new evidence painted just as chilling a picture: James Holmes had a series of meticulously laid traps waiting for first responders, right down to a frying pan.

FBI bomb technician Garrett Gumbinner submitted testimony in Arapahoe County District Court about the elaborate series of bombs awaiting law enforcement officers who arrived at the scene of Holmes's apartment shortly after he allegedly opened fire at the Century 16 theater. Gumbinner, who was one of the agents who interviewed Holmes just after the shooting, recalled, "He said he rigged his apartment to explode or catch fire in order to divert police resources to his apartment." 

The disturbingly MacGyvered rigging involved jars packed with napalm, blaring music, a remote controlled car, and an improvised tripwire. A thermos full of glycerine hung over a frying pan loaded with oxidizing crystals. One of Holmes's thwarted plots, as outlined by Gumbinner, would've gone like this: A computer programmed to play about a half-hour of silence before launching into some high-volume music would've forced annoyed neighbors to call the cops. Upon responding, the police would've triggered an explosion by stepping into tripwire strung across the front door. "It would have caused fire and sparks," said Gumbinner. The gasoline-soaked carpet "would have made the entire apartment explode or catch fire." And the white powder sprinkled on Holmes' carpet—ammonium chloride—would've produced a lot of smoke which Gumbinner says was meant "to scare us."

Another detonation scenario would've been set in motion by a remote controlled car. Holmes had apparently placed another set of pre-programmed speakers in a trash bag just outside the apartment. If someone were to have approached the noisy trash bag, picked up the remote control, and tried to drive the car, they would've set off a second set of bombs located in the apartment. Perhaps the most unsettling thing revealed by Tuesday's testimony from an ATF agent is that Holmes acquired all the chemicals to build these traps legally, according to ABC News's Carol McKinley and Christina Ng.