NEVER-before-seen footage has revealed exactly what happened in the Uvalde school shooting following debate over its release.
The shocking surveillance video shows gunman Salvador Ramos stalking the halls of Robb Elementary on May 24 in an attack that left 21 people dead.
The footage was initially viewed by Austin American-Statesman and 's Tony Plohetski.
Plohetski, an award-winning investigative journalist, said one security camera placed at the end of a hallway inside the school captured "the horror and devastating law enforcement mistakes."
A 77-minute recording from that camera shows the "clearest accounts" of what happened before and after Ramos killed 19 students and two teachers and left 17 others injured.
The American-Statesman reporter said that the suspect could be seen wearing all black with a backpack as he calmly walks into the back entrance of the school with an AR-15.
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At 11.33am, the gunman is seen looking at a classroom door before turning right into the main corridor.
Moments after he walks away, a boy is seen witnessing the start of gunfire and turns and runs away, appearing to escape.
Shortly after, the footage shows the gunman shooting toward a classroom before walking in.
Police are seen walking into the building just three minutes after the suspect arrived, however, they didn't go into the classrooms until about 12.50pm.
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At one point, officers are seen running toward the classroom but made their way back down the hallway after the gunman returned fire.
One heavily armored police officer is seen using hand sanitizer while others restrain a cop identified as Sheriff's Deputy Felix Rubio.
His daughter Lexi, 10, was shot dead in the massacre.
Another officer appears to check his phone.
According to KVUE, 13 rifles are seen on the surveillance footage within the first 30 minutes of police arriving, and a shield arrived within 20 minutes.
In response to the release of the footage, Texas DPS Director Steven McCraw said: "I am deeply disappointed this video was released before all of the families who were impacted that day...Those most affected should have been among the first to see it."
SHOCKING IMAGES
Last month, shocking images emerged showing armed Uvalde cops waiting outside classrooms in Robb Elementary School for 46 minutes.
The photos, first published by , show police standing in a line behind shields while holding their weapons.
According to the outlet, the police pictured in the hallway of Robb Elementary School wanted to get inside classrooms 111 and 112 as quickly as possible.
They were pictured at the end of a hallway, alongside the blue-and-green school walls at 12.04pm on May 24, 2022.
It wasn't until 12.52pm when border patrol agents entered the classrooms and killed the gunman.
The Texas Tribune wrote: "Most of the video from inside the school is captured by a wide-angle camera positioned inside the school building’s northwest entrance, the same one the gunman used.
"The camera looks straight south from its north ceiling perch and offers a slight view of the entrances to classrooms 111 and 112 to the left."
As police waited to enter, one officer's daughter was inside the classrooms and another cop's wife, a teacher, called her husband to say she was bleeding to death.
'NO ATTEMPT TO OPEN DOOR FOR 77 MINUTES'
But cops never tried to open the door to classrooms while gunman Ramos massacred people for 77 minutes, footage has shown.
The police force in Texas previously claimed they could not open the door to classrooms where children and teachers were huddled because a key didn't fit.
Meanwhile, as parents and family members of Robb Elementary students waited anxiously outside the school for updates, some children were able to escape through windows with the help of officials.
Border Patrol and local police worked together to pull children out through windows and direct them to safety during the shooting.
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CHILLING FOOTAGE
Additional footage near the school showed Ramos approaching the building with what sounds like gunfire going off in the background.
The video was shared on social media as concerned parents raced to the school searching for their children.