During chilling testimony Tuesday morning, an FBI technician revealed just how many more people could have died in Aurora, Colo., had someone gone in James Holmes' apartment.
FBI bomb tech Garrett Gumbinner said Holmes told police he wired his apartment to cause an explosion that would divert law enforcement's attention away from the movie theater, The Denver Post's John Ingold tweeted.
Holmes' apartment contained jars filled with homemade napalm and thermite, the carpet was soaked in gas, and a thermos filled with glycerin was perched over a frying pan filled with chemicals, according to Ingold and The Denver Post's Jessica Fender.
A trip wire laid across the door would have tipped the thermos into the chemical, causing them to spark and catch the carpet on fire, had the apartment door been opened, The Denver Post reported.
Holmes reportedly purposely set his stereo to play loud music in the hope the music would cause someone to come to the apartment and hit the trip wire.
Holmes also told police he put a "pyrotechnic firing box" that was connected to six-inch firing shells on top of his computer, Ingold tweeted.
The box was meant to be used as a trigger for the bombs.
Holmes planted the remote on a remote-controlled car outside, hoping someone would play with the car, which would set off the explosives, 9News' Jeremy Jojola tweeted from the courthouse.
In total, authorities found fireworks shells, 10 two-liter Sprite bottles filled with gas, three jars of homemade napalm, and smokeless powder in Holmes' apartment, Fender tweeted.
As testimony continued Tuesday, ATF agent Steven Beggs testified Holmes also bought two Glocks and 2,600 rounds of ammunition for them, one shotgun plus 325 rounds of ammunition for it, and one assault rifle plus 3,370 rounds of ammunition for it, Fender tweeted.
Holmes also reportedly bought explosive chemicals in the months leading up to the shooting as well as shooting targets.
While the prosecution claimed to have some surveillance videos showing Holmes buying his artillery, most of it was bought online.
Testimony from Monday's hearing revealed at least 33 bullets were used to kill the 12 victims. Witnesses testified Tuesday that Holmes reportedly bought a movie ticket for theater 8 but instead went into theater 9.
Police don't know why he did that.
Holmes, who sported a full beard and brown hair in court, is facing more than 160 charges after he allegedly opened fire on a theater full of people during The Dark Knight Rises midnight premiere in Aurora, Colo.
Tuesday's hearing was also filled with heartbreaking details as prosecutors released tapes of 911 calls from those trapped in the theater.
A 14-year-old cousin of Veronica Moser-Sullivan — the 6-year-old girl who died in the shooting — could be heard on tape "weeping" as Veronica and and her mother Ashley Moser lay injured, Fender tweeted from the courtroom.
"My two cousins, they're sitting on the floor... one of them" is not breathing, the teen girl said, according to the Post.
The cousin was 13 at the time of the shooting.
"I can't hear.. It's too loud... I can't hear you. I'm so sorry," the girl could be heard saying as a 911 operator tried to walk her through CPR, according to Fender.
Cops began arriving at the Century 16 theater in Aurora, Colo., about 18 minutes after the movie began a little after midnight.
Emergency dispatch received 41 calls in the first 10 minutes of the shooting.
The first emergency call came from Kevin Quinonez, according to Fender.
"There's some guy...after us," Quinonez said in his call, according to the Post.
Aurora Police Department Det. Randy Hansen counted 30 gunshots during Quinonez's call, Fender tweeted.
While Holmes showed absolutely no emotion either day in court some police officers broke down and cried on the stand as theytestified about the horrific scene they encountered at the theater.
Officer Justin Grizzle also talked about walking into the theater and seeing "several bodies throughout the theater laying motionless," Fender tweeted from the courtroom.
Grizzle testified there were so many victims he was slipping in blood as he entered the theater.
Many victims also became emotional in court, often choking back tears or hiding behind handkerchiefs.
Court ended Tuesday evening around 5 p.m. local time. There is a chance tomorrow could be the last day of the preliminary hearing since the prosecution is on its last witness, according to Ingold.
Check out a full rundown of the first day of Holmes' preliminary hearing >
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