UVALDE, Texas - A screen grab from a security camera inside Robb Elementary School in Uvalde, Texas is raising questions about the police response to the shooting spree.

The image, obtained by the Austin American statesman, shows officers in the hallway of the school with rifles and a shield at 11:52 a.m., 19 minutes after the gunman entered the school.

The Austin American statesman said the timeline was based on documents it reviewed following the May 24th attack that killed 19 children and two teachers.

The Texas tribune on Monday night also reported the new details, citing records and surveillance video it had reviewed.

NBC news has not seen or reviewed the documents, but the reports could raise further questions about the long delay before officers breached the classroom doors and killed the 18-year-old gunman.

It was around 80 minutes from when the gunman entered the school around 11:33 a.m. and when police entered the classroom around 12:50 p.m. and killed him, according to official accounts.

According to the statesman, a reconstructed timeline shows officers were inside the school three minutes after the gunman entered.

Pete Arredondo, police chief for the school district, at 11:40 a.m. called Uvalde police for help and said, we have him in the room. He's got an ar-15. He's shot a lot," according to the statesman.

Arredondo said also said they need to be outside the building prepared because we don't have firepower right now" and it's all pistols," according to the newspaper.

A lawyer for Arredondo did not immediately respond to a request for comment on the reports Monday night.