AUSTIN, Texas — Multiple police officers stood in a school hallway armed with rifles and at least one ballistic shield within 19 minutes of a gunman arriving at the campus in Uvalde, Texas, according to documents reviewed by the American-Statesman, further raising questions whether any lives could have been saved during the deadly attack.

Even as officers with high-powered weapons and ballistic shields massed inside the blue and green hallway, the gunman could be heard firing rounds — including at 12:21 p.m., 29 minutes before officers entered the classroom and killed him, the documents show. 

Investigators say the latest information indicates officers had more than enough firepower and protection to take down the gunman long before they finally did. The massacre killed 19 children and two teachers at Robb Elementary School.

Much of the new information  is expected to be presented at a Texas Senate hearing Tuesday, the first of two consecutive days of hearings at the state Capitol that will give members of the public their first opportunity to address lawmakers on gun violence and related issues. 

The law enforcement response has been scrutinized by state and federal investigators since shortly after the massacre. On May 27, Texas Department of Public Safety Director Steve McCraw revealed that officers waited more than 70 minutes to confront the shooter, even as trapped fourth graders inside two classrooms were desperately calling 911 for help.

The delayed response ran counter to widely accepted law enforcement protocol, developed from many similarly horrific school shootings nationwide, that calls for officers to stop the shooter promptly and resolutely.

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The latest timeline revealed in the investigative documents reviewed by the Statesman, part of the USA TODAY Network, shows that officers ultimately breached a classroom door at 12:50 p.m.; the shooter had entered at 11:33 a.m.

Authorities have reconstructed the events of May 24 using footage from inside the school, which showed the gunman casually entering a rear door, walking to a classroom and immediately spraying gunfire before barricading himself. The timeline also was built using body camera video from more than a dozen officers inside the school.

According to the new information, 11 officers entered the school within three minutes of the gunman. Pete Arredondo, chief of the Uvalde school district police force, called a landline at the Uvalde Police Department at 11:40 a.m. for help.

“It’s an emergency right now,” he said. “We have him in the room. He’s got an AR-15. He’s shot a lot . . . They need to be outside the building prepared because we don’t have fire power right now,” he said. “It’s all pistols.”