CENTENNIAL, CO - The recording is loud, chaotic and difficult to understand. There's too much sound to make out what the caller is saying.
Just one thing is unmistakable: the sound of gunshots.
At least 30 of them. In 27 seconds.
Prosecutors on Tuesday played the first 911 calls from the July 20 Aurora, Colorado, movie theater shooting as they continued building their case at a preliminary hearing for James Holmes, the 25-year-old former neuroscience graduate student accused of killing 12 people at a midnight showing of "The Dark Knight Rises."
Detective Randy Hansen testified that the first call to authorities came 18 minutes after the film started. More trickled in until the torrent was complete: 41 calls in all, he said.
Because the movie was still playing and, in at least one, the gunman was still stalking the theater, the calls are difficult to make out. In one, a 13-year-old girl called to say her cousins had been shot. A 911 operator tried to lead the sobbing girl through performing CPR on one who was still breathing.
Family members of victims attending the hearing held each other and choked back tears as the calls were played.
After detailing the calls, prosecutors turned to the intricate explosive web authorities say Holmes left in his apartment, including jars of homemade napalm with bullets suspended inside and topped with thermite, a material that burns so hot, it's nearly impossible to put out.
In photos displayed in court, the mixture looked like amber-colored gelatin.
Elsewhere in the sparsely decorated apartment, a container of glycerin hung connected to a tripwire, ready to tip into a frying pan that held a homemade substance that would have sent sparks flying onto carpets soaked in oil and gas -- setting them aflame, FBI bomb technician Garrett Gumbinner testified. A robot sent inside discovered the tripwire.
He said Holmes also left a boombox by a trash container outside his apartment rigged to start playing loud music 40 minutes after he turned it on.
Next to it, he left a remote-control toy car and a control device, Gumbinner testified. However, the remote wasn't to operate the car. If a passer-by had used it, it would have triggered the explosives in his apartment, he said.
The details came on the second day of Holmes' preliminary hearing, which could last all week. It is meant to prove to Arapahoe County District Judge William Sylvester that prosecutors have enough evidence to proceed to trial.
Holmes' attorneys are expected to seek a "diminished capacity" defense that could prevent the case from getting that far.
In Monday's first day of testimony, police officers recounted arriving at the movie theater to find a detached, sweaty Holmes outside and a horrific scene inside the theater, where the floor had become slippery with blood and cell phones rang unanswered.
While none of the law enforcement witnesses who testified Monday offered insight into a possible motive for the shooting, some new details emerged.
Prosecutors aired surveillance camera video taken inside the theater complex that shows a man they say is Holmes dressed in dark trousers, a light-colored shirt with a T-shirt underneath and a ski cap. In the video, the man is shown using a cell phone at a ticket kiosk.
Holmes printed out a ticket that had been purchased on July 8, they said.
After going into the theater, Holmes apparently popped a small plastic piece commonly used to secure tablecloths onto an outside door, preventing it from closing, Police Sgt. Gerald Jonsgaard testified. Authorities believe Holmes then went outside, armed himself and returned to the theater to begin killing.
While no cameras captured the shooting inside the theater, cameras outside captured the aftermath as waves of people ran out. One employee leaped over a counter to escape.
Police Officer Jason Oviatt, the first officer to encounter Holmes after the rampage ended, testified Monday that Holmes seemed "very, very relaxed."
Holmes, sweating and smelly, his pupils dilated, didn't struggle or even tense his muscles as he was dragged away to be searched.
"He seemed very detached from it all," Oviatt testified, describing Holmes as unnaturally calm amid the chaos and carnage.
Aurora police Officer Justin Grizzle, a 13-year veteran, wiped away tears Monday while describing his efforts to rush badly wounded victims to a hospital in his police cruiser, including shooting victim Ashley Moser and her husband, who wanted Grizzle to turn around and head back to the theater.
"He was shot in the head somewhere. He kept asking where his ... daughter was," Grizzle said. "He opened the door and tried to jump out."
Grizzle said he had to drive and hold the man by his shoulder to keep him in the car.
The girl the man was seeking, 6-year-old Veronica Moser-Sullivan, was shot four times and was among those killed. Veronica's mother, Ashley, faces a long recovery after being paralyzed in her lower body and miscarrying after the shooting.
The scene was still gruesome