Four Uvalde shooting victims left classrooms alive. Investigators are reviewing whether a faster response could have saved them.

Crosses are on display on May 26 for the people killed at Robb Elementary School. (Lauren Witte/The Texas Tribune, Lauren Witte/The Texas Tribune)

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Investigators conducting a criminal probe into the Uvalde school shooting and subsequent law enforcement response are trying to determine whether any victims who died may have survived if police had intervened sooner.

Four victims — teacher Eva Mireles and three students — who had heartbeats when they were rescued from adjoining classrooms in Robb Elementary died that day. They had been trapped with the shooter for more than an hour.

The Texas Rangers have asked Dr. Mark Escott, medical director for the Texas Department of Public Safety and chief medical officer for the city of Austin, to look into the injuries of the victims. In a statement, a city spokesperson said Escott will “lead an analysis of the injuries sustained by the Uvalde shooting victims to determine whether there may have been opportunities to save lives had emergency medical care been provided sooner.”

[“I’m so scared”: 911 recordings reveal fear and urgency of those trapped in Uvalde elementary school]

“Similar reviews have been conducted in the past following mass shooting incidents to learn lessons, influence policy development and improve responses to future incidents,” the spokesperson said.

Details of the inquiry, which is in its early stages, were first reported Thursday by the Austin American-Statesman. Officials with DPS did not immediately respond to an email.

Escott said in an interview that he contacted DPS shortly after the shooting to ask if the analysis could be conducted. He was familiar with similar reviews that had been done after other mass shooting events and how they can inform EMS and law enforcement policy as well as public policy. While he has received some information from DPS since the late summer, he said he is still missing finalized autopsies, which will be key for the examination.

Nineteen children and two teachers were killed in the May 24 shooting at Robb Elementary.

"I think the analysis will help to answer the key question: If medical care had been able to be provided sooner, would it have made a difference? And if so, for how many people?" Escott said. "I don't know what this analysis is going to show but it will be objective, it will be complete and it will answer the questions."

He added in past mass shootings there is evidence that some victims could have survived if medical care was provided sooner, but in those cases the victims were adults.

“In speaking to researchers, who've done analyses on children who've been shot with rifles, that number has been zero,” he said. He also said that in some cases, depending the on the severity of the wounds, the fact that first responders transported victims to hospitals does not mean that the victims could have survived.

“In general, the fact that that patients are transported to hospitals or resuscitation is attempted, does not necessarily mean that they have injuries which are survivable,” he said. “It's not uncommon, particularly with injuries like gunshot wounds to the head, where individuals may stay alive for minutes, sometimes hours, sometimes longer. But ultimately, the injury that they have is not a survivable injury.”

Eulalio “Lalo” Diaz Jr., a justice of the peace in Uvalde who was the on-duty coroner on May 24, said in an interview last month that he thinks four victims who were transported out of the school — Mireles, Jackie Cazares, Jose Flores and Xavier Lopez — may have survived if first responders got them medical attention sooner. He also noted that there were other injured teachers and students who survived even after police waited more than an hour to enter the classroom where the gunman was.

“Could more have survived? Probably. We won’t know until the final autopsy report comes out from the medical examiner,” he said. “That’ll tell you exactly where they were shot. What injury happened if they hit a major artery, or if it was just a wound in the torso area that allowed them to bleed out a longer period of time. I won’t know that, I won't be able to tell you for sure. But just the fact that some people did survive tells you that maybe they could have, everybody has a different situation and a different type of wound.”

Nearly 400 law enforcement officers responded to the shooting, but none breached the classroom full of kids where the gunman was for more than an hour after the shooting began, even as some children in the rooms called 911 for help.

The district attorney in Uvalde, Christina Mitchell, has called the investigation a criminal inquiry but has not shared much information about whether charges will be brought against any officers who responded. She reiterated earlier this week that she had not made any charging decisions yet.

“I will be unable to make a decision as to potential charges on anyone, including law enforcement, until I receive the complete investigation,” Mitchell said. “I have consistently stated that if the criminal investigation reveals any conduct or lack of conduct which meets the elements of a criminal offense in the state of Texas, I will seek an indictment by a Uvalde grand jury.”

Mitchell did not immediately respond to an email Thursday morning.

In an interview in August, she said the completed criminal investigation would be presented to a grand jury, which will determine if anyone should be charged with a crime. She said the criminal investigation will look at “every adult that was in that building.”

“I don’t know if we will have criminal charges until their investigation is complete," she said. I' don’t know that we are and I don’t know that we’re not. Therefore, I want them to do a complete and thorough investigation. And then the case will be presented to a grand jury and then we will know.”

Texas Rangers expect to finish their part of the investigation by the end of the year and send their findings to the district attorney, DPS Director Steve McCraw said last week.

In September, McCraw said that he would resign if his troopers had “any culpability” in the flawed response. Ninety-one of the 376 law enforcement officers who responded were from state police.

Facing calls to resign last week, McCraw said, “DPS as an institution, right now, did not fail the community.” If it did, he said, he would resign.

He added, during a Public Safety Commission meeting, that the actions of all troopers would be scrutinized.

“The question is how many kids did die in that room, or teachers died, because they missed that ‘magic hour,’” he said, referring to a critical period during which someone suffering from survivable injuries must be treated. “You gotta stop the dying. And they were in there with an active shooter and we didn’t get through that door, we didn’t go through the windows, plain and simple, and we — law enforcement — should have done it.”