A newspaper in the southeastern U.S. state of Texas has posted surveillance video of the police response to the shooting rampage at an elementary school in May that left 19 children and two teachers dead.

The edited video posted Tuesday on the website of the Austin American-Statesman shows 18-year old gunman Salvador Ramos crashing his truck outside Robb Elementary School on May 24 and firing his high-powered assault rifle at the school as the voice of a teacher screaming at students to get in their rooms is heard during a frantic call to an emergency operator.

Ramos is then seen entering the school and walking the hallways until he enters a classroom, followed by the sounds of rapid gunfire. Police enter the school just minutes later, with some officers rushing towards the classroom before retreating as more gunshots are heard.

More officers enter the school, some carrying body armor. But the edited video shows the officers still gathered at the end of the hallway over the course of 77 minutes without mounting a rescue effort, even after more gunshots were heard. Two U.S. Border Patrol officers finally stormed the classroom and shot and killed Ramos to end the massacre.

The failure of Uvalde law enforcement agencies to immediately confront Ramos — as well as the investigation into the shooting — has angered parents and the Uvalde community at large. The Texas Department of Public Safety issued a report earlier this month saying a Uvalde police officer missed a chance to shoot Ramos before he entered the school because he was waiting for permission from a supervisor.

The Statesman says it posted the video to “continue to bring to light what happened at Robb Elementary, which the families and friends of the Uvalde victims have long been asking for.” But Uvalde Mayor Don McLaughlin denounced the newspaper during a town council meeting Tuesday, calling its release of the video “one of the most chicken things I’ve seen.”

The mayor said that the video should not have been released until it was seen by the victims’ families.

Some information for this report came from The Associated Press, Reuters, Agence France-Presse.