He dyed his hair bright orange, then bought a scope and non-firing dummy bullets on July 1, the visit and the new hair color documented in security video.
Finally, he purchased glycerin and potassium permanganate — chemicals that could combine to create fire — from a Denver science store. At some point, he also improvised napalm, as well as thermite, a substance which burns so hot that water can't extinguish the blaze.
Holmes' purchases were for two planned attacks, prosecutors said — the theater shooting and the booby-trapped apartment that would have blown up if anyone had entered.
The bottle of glycerin was meant to fall into the permanganate when the door to his apartment opened, to cause an explosion and then a fire, prosecutors said.
Parts of Holmes' carpet were soaked with gasoline and oil, and ammonium chloride, a white powder, was poured onto the floor in strips, FBI bomb technician Garrett Gumbinner said.
"It would have ignited and the whole apartment would have exploded or caught fire," Gumbinner said.
He said the rig had two other initiating systems. One was a pyrotechnics firing box that would have been triggered by the remote control unit of a toy car left along with a boom box set to play loud music. Gumbinner said Holmes told him he hoped the music would lure someone and lead them to play with the car, thereby detonating the explosives.
The other was a model rocket launch box that operated by means of infrared light, but Holmes told investigators it wasn't armed, Gumbinner said.
The attempt at a distraction speaks to a plan to escape, but the traps weren't triggered. Holmes, clad from head to toe in body armor, was found standing by his car outside the theater. He told investigators that the booby-trapped apartment was an effort to pull police away from the theater. He didn't expect to see officers so quickly.