This story is part of a KXAN series of reports called “Stop Mass Shootings,” providing context and exploring solutions surrounding gun violence in the wake of the deadly Uvalde school shooting. We want our reports to be a resource for Texans, as well as for lawmakers who are convening a month after the events in Uvalde to discuss how the state should move forward. Explore all “Stop Mass Shootings” stories by clicking here.

AUSTIN (KXAN) — State investigators released a new timeline during Tuesday’s Texas Senate committee hearing detailing the more than 70 minutes officers spent inside Robb Elementary as a gunman opened fire on children and teachers.

The timeline, which is compiled from footage from a nearby funeral home, school surveillance, 911 recordings and body-worn camera, details more than 100 rounds being fired as armed officers entered the Uvalde school building. 

Eight officers were in the building three minutes after the shooter entered, including Uvalde CISD Chief Pete Arredondo. Officers who approached the classroom doors were injured, according to the Texas Department of Public Safety timeline.

“You run to the sound of gunfire; you do not stop. There is no doubt in mind that any one of those officers would have sacrificed their lives for those children,” said Texas DPS Director Steven McCraw.

The timeline shows officers were inside the building for an hour and 14 minutes before the gunman was shot by law enforcement. During that time, multiple officers questioned whether there were children inside the classrooms.

According to the timeline, a unidentified officer asked “y’all do not know if there’s kids in there?” A Texas DPS special agent responded, ‘if there’s kids in there, we need to go in there.”

McCraw testified Tuesday that 28 minutes after officers arrived on the scene, a 911 call came in from one of the students inside the classroom where the shooting was happening.

“That was the first time Chloe called. It was heart wrenching. She was the only one [in the room] that was uninjured,” said McCraw.

The timeline shows for more than 40 minutes Arredondo and officers were trying to figure out how to get the doors open to the classroom, including the chief asking for a master key and for a door-breaching tool.

“There’s a window over there obviously. The door is probably going to be locked,” said Arredondo at 12:28 p.m., according to the Texas DPS timeline. “I am going to get some more keys to test.”

However, DPS Director McCraw said Tuesday he believes the classroom doors where the shooter was located were “unsecured” and not locked.

“The officers had weapons; the children had none. The officers had body armor the children had none. The officers had training; the subject had none. One hour 14 minutes and 8 seconds — that’s how long the children waited, and the teachers waited in room 111 to be rescued,” said McCraw. “While they waited the on-scene commander waited for radio and rifles. Then he waited for shields. Then he waited for SWAT. Lastly, he waited for a key that was never needed. The post columbine document is clear and compelling and unambiguous stop the killing stop the dying”