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As acting Uvalde police chief resigns, questions remain about what Texas's top law enforcement agency did and didn't know about the school shooting

Uvalde, Texas(CNN) New audio obtained by CNN shows Texas's top law enforcement agency knew children were trapped in Robb Elementary more than 30 minutes before anyone shot the gunman and rescued them.

Less than two minutes after the acting Uvalde police chief Lt. Mariano Pargas got details that children were alive amid classmates massacred in their classroom, essentially the same information was shared with someone at the state's Department of Public Safety (DPS).

Pargas, 65, resigned Thursday, two days before a "special meeting" called by the City of Uvalde to decide his fate. The rare Saturday evening meeting was scheduled after CNN revealed he knew a girl was calling from the classroom saying eight or nine children were still alive and he failed to organize help.

It's not clear how DPS's internal investigation is looking at communication failures. The department announced it was reviewing the actions of the 91 DPS officers who made it to Robb Elementary on May 24, the day 19 children and two teachers died while a shooter holed up in classrooms for 77 minutes.

Those failures would include what happened at the headquarters in Austin, as well as how information was shared by phone, text messages and radio.

'Robb Elementary? Oh my god'

The new audio obtained by CNN reveals a woman from "DPS in Austin" calling the Uvalde police dispatchers to get more information apparently to give to the specialist DPS teams being sent to help, including SWAT.

The caller is clearly shocked as she gets the details that the killings have happened in an elementary school.

"Robb Elementary? Oh my god," she says.

When the dispatcher tells her, "We have several DOAs (deaths)" she interrupts: "Are you kidding me?"

"I am not," replies the dispatcher.

"Oh my god," the DPS employee sighs. "OK."

She gets details of the shooter and that he is still in the school with students before ending the call at about 12:20 p.m.

CNN does not know the caller's rank inside DPS, or where else she may have communicated the information within her agency.

DPS has not responded to CNN's questions about the call and what happened after it was made.

But it is clear that the information given in the phone call between Uvalde and Austin -- that children were in the school with the shooter and that people had already been killed -- was not shared sufficiently.

The statewide DPS helps local law enforcement agencies with major incidents and has specialized equipment and teams that smaller city and county forces may not have.

Many teams were sent to Uvalde, but the critical information that should have supercharged the response and focused on stopping the killer and rescuing the victims instead of waiting him out, was not given to them.

While Pargas could have changed the dynamic of the operation that had stalled, as could other leaders on scene, so could DPS chiefs.

But the urgency of children and teachers needing help appears to have abated in a communication morass.

Hunt for information

Capt. John Miller, the DPS SWAT commander, deployed his entire team when they were notified of the active shooter at about noon on May 24, even though almost all were at least 175 miles away, he told an investigator, according to interview records obtained by CNN.

But once they were on the road, they didn't get new information, he said. "Initially the word was there's a barricaded shooter, but he's shooting at law enforcement in a school," he said. "There was no information after that regarding if there was hostages."

He said he then spent many minutes trying to find out what was going on so he could make an appropriate plan, critically to account for any innocent people with the shooter.

"For the next 40 minutes, the series of phone calls and messaging on my end was all trying to find that out," he told the investigator.

Only one member of Miller's team made it to Robb Elementary before law enforcement breached the classroom and killed the shooter at 12:50 p.m.

And his first task was also trying to find out whether children were trapped.

"I talked with the highway patrol sergeant and asked her if there were still kids inside the building that the shooter was in," Staff Sgt. Lucas Patterson told a Texas Ranger investigating the response, according to the records CNN has obtained. "She wasn't positive on that from information, she was trying to verify."

The failed information flow didn't just affect the DPS SWAT team that was mentioned in the 12:18 p.m. call to Uvalde dispatch.

DPS Capt. Joel Betancourt told investigators: "The only thing that was being reported was that it was a barricaded subject. There were no shots that had been fired anymore. We didn't know that there was any children or anybody that was injured in the building like we do now. At that time, it was just a person in a room."

Even so, Betancourt issued a radio order to the breach team to stop their advance to the classroom, believing a better team was on the way, as previously reported by CNN. No one responded to his call.

That breach that stopped the gunman came more than 30 minutes after details of children trapped were given to Pargas and DPS.

The actions of DPS that day, and soon after when senior leaders gave conflicting accounts of what had happened, as well as how they have been tasked with investigating the response, continue to trouble Uvalde Mayor Don McLaughlin who told CNN again this week he believed there was a cover-up. DPS Director Steven McCraw has rejected that suggestion.

A total of 376 law enforcement officers from 23 agencies -- including 91 men and women from DPS -- responded to the Robb massacre.

Along with personnel, an arsenal of specialist equipment was deployed, much of it by DPS, apparently without a clear plan as to whether it was needed.

"Two DPS helicopters, one with an AUF package -- an aerial shooter -- and that's going to be about 25-30 minutes," an officer tells Uvalde dispatch a little after 12:30 p.m. After requesting a "real-time update" and having confirmed the location was Robb Elementary, he added: "I'm trying not to be a pest, but we're trying to coordinate."

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