CENTENNIAL, Colo. (USA TODAY) - An FBI bomb technician testified Tuesday that mass murder suspect James Holmes rigged his apartment with a series of homemade bombs that could be accidentally detonated, decimating his apartment building and creating a diversion away from shootings at a movie theater in Aurora.
Garrett Gumbinner, in the second day of a preliminary hearing, said Holmes booby-trapped his apartment with an array of homemade explosives that would be tripped when the front door was opened. The setup included materials as elaborate as napalm and glycerine mixed with potassium magnate, and the carpet was soaked in gasoline and oil, so it could catch fire.
Gumbinner detailed how Holmes rigged the door with fishing line so when it opened, a thermos filled with glycerine would spill into a pan full of potassium magnate, setting off sparks.
Gumbinner said Holmes planned to use a remote-controlled device to set off the explosion.
Authorities conducted a controlled detonation at his apartment and used a robot driven by a bomb technician to methodically disable the explosive devices.
The preliminary hearing is to determine whether there is enough evidence to try Holmes on more than 160 counts of murder and attempted murder charges. Holmes is alleged to have killed 12 and wounded 57 during the theater shooting July 20.
Earlier in the hearing Tuesday, witnesses testified about some of the chilling 911 calls that came from the theater as the shooting began.
Detective Randy Hansen said there were 41 separate calls within the first few minutes of the shooting.
The first call to police played in court came from inside the theater from Kevin Quinonez at 12:38 a.m. Hansen said during the 27-second call he heard at least 30 gun shots. The call came in 18 minutes into the showing of The Dark Knight Rises.
Police also played a 911 call from a teenage cousin of 6-year-old Veronica Moser-Sullivan, the youngest person killed. Screams could be heard in the background as the dispatcher tried to talk her through CPR. She sobbed and said she couldn't hear and couldn't do it.
Holmes stared straight ahead as the calls were played and didn't show any emotion.
Aurora Police Detective Tom Welton also testified Tuesday that Holmes opened accounts on Internet dating websites match.com and AdultFriendFinder.com, labeling both with headlines "Will you visit me in prison?" He last accessed the match.com account on July 18. The AdultFriendFinder.com account was created July 5, Welton said.
Welton's testimony, which came over the objections of defense attorney Dan King, shows Holmes had planned to commit a crime, prosecutors said. The shooting happened on July 20.
Also revealed Tuesday: Holmes bought a .40 caliber Glock on May 22 at a Gander Mountain store in Aurora; a second Glock on July 6 at another Bass Pro shop store in Denver; a Remington tactical shotgun on May 28 at a Bass Pro shop; and a Smith & Wesson AR 15 assault rifle on June 7 from another Gander Mountain store in Thorton.
On Monday, Arapahoe County prosecutors began laying out evidence against Holmes with a series of Aurora police officers, detectives and forensics experts who provided often emotional testimony about the mayhem they encountered when they arrived at the suburban Denver movie theater.