The first call from the Aurora police dispatcher comes in at 12:39 am, a little over half-an-hour after the start of a midnight showing of the new Batman film, "The Dark Knight Rises."

"Shooting at Century Theater. They're saying someone is shooting in the auditorium," the female dispatcher says.

"There is at least one person that has been shot but they're saying there are just hundreds of people running around," she says. "All available units respond to the theater."

Audiotapes of conversations between police and ambulance personnel paint a harrowing picture of Friday's rampage in a downtown Aurora movie theater which left 12 people dead and another 58 wounded.

Police were on the scene within 90 seconds after the first report of gunfire at the Century Aurora 16 theater in this town outside of Denver, Colorado.

As police were responding, so were ambulance teams.

"We are having units get to the scene now," an ambulance dispatcher says. "There may still be someone actively shooting.

"Engine 8, Battalion 1, Medic 109. They need you hot to the front of the theater," she says. "So far we have one party down."

Shortly afterwards, the dispatcher sends more ambulances to the scene.

"Engine 8 we may have additional victims. We're starting a second ambulance," she says.

"We're actually starting a third ambulance," she says moments later, adding that the situation appears to be a "shooting with multiple victims, at least three at this point."

The ambulance dispatcher also tells the units responding that they are "going to need gas masks."

"There was gas being sprayed inside the theaters," she says.

According to police, the alleged gunman, James Holmes, a 24-year-old medical student at the University of Colorado, threw two canisters containing tear gas or smoke into the theater before opening fire on moviegoers.

Holmes was arrested without resistance by his car outside the theater and the police tapes detail his capture.

"(Police) cars with that white car in the rear of the lot is that a suspect?" a police officer asks.

"Yes, we've got rifles, gas masks. He's detained right now," another officer responds.

"Hold that position, hold your suspect," the first officer says.

The ambulance dispatcher says meanwhile that the "PD (police department) is requesting as many ambulances as possible."

"I'll start two more engines," she says.

As the scale of the disaster emerges and the dispatcher sends even more ambulances to the scene, medics are reporting back to her on casualties.

"I'm down here north of the Century," a member of an ambulance team says as sirens can be heard in the background. "I've got a female with a GSW (gun shot wound) to the leg. I'm going to get her loaded up and get going."

Another team reports that it has "five reds (wounded)."

"We are in the rear of the theater. We have nine shot," reports another medic. "Right now we're loading patients in the back of PD (police) cars to get them transported. Any ambos (ambulances) we could get would be nice."

At one point, the coordinator of the emergency response on the scene asks the dispatcher "How many ambulances do I have?"

"I don't know an exact count of ambulances," she replies. "We have every unit that's available in the city of Aurora."

While the wounded were being transported to hospitals, the first reports began to emerge of the dead inside the theater.

"We have transported seven patients, we're on our eighth patient," says a member of an ambulance team "Also, we just talked to police officers who said we may have a number of people dead inside the theater."

"OK, if they're dead, just leave them," his commander responds. "We're in a mass casualty situation at this time."