Police allegedly tried to stop the teen gunman before he stormed an elementary school in Texas and shot dead 21 people — including 19 students and two adults — when he crashed his car in a nearby ditch.
Gunman Salvador Ramos, 18, earlier shot his grandmother at her home before fleeing the scene by car and crashing near the school where he jumped out with a rifle and a backpack.
Ramos tried entering the school where he was approached by police, Sergeant Erick Estrada from the Texas Department of Public Safety told CNN.
But the 18-year-old was able to enter the premises where he "started shooting his firearm" and subsequently killed at least 21 victims.
"The suspect did crash near a ditch nearby the school," Sgt Estrada told CNN on Tuesday.
"That’s where he exited his vehicle with what I believe was a rifle, and that’s when he attempted to enter the school where he was engaged by law enforcement.
"Unfortunately, he was able to enter the premises and then from there that’s when he entered several classrooms and started shooting his firearm."
It's believed the gunman was seen "wearing body armour" and had with him a "long rifle and backpack," Sgt Estrada said.
In a Tweet on Tuesday, journalist and founder of Talking Points Memo, Josh Marshall, said, presumably, this is how the gunman was "able to fight his way in", saying "cops exchanged gunfire with him" before he entered the school.
Despite the armour, the teen was later shot and killed by police, it was confirmed.
Gunman shoots his grandmother before school attack
The grandmother of Ramos is in hospital in critical condition, Sgt Estrada confirmed.
The elderly woman was airlifted to San Antonio and "is still holding on," according to information released by the Texas Rangers.
"This young man shot his grandmother and fled that scene from that incident,” State Sen Roland Gutierrez told CNN.
Following the brutal massacre, an unverified video was shared on social media which appears to show a man, believed to be Ramos, moving between school buildings.
The person can be seen lurking beside a car park before disappearing out of shot.
The students who were killed or injured in the attack were either in the second, third or fourth grade. Typically, they're aged between 7 and 10 in the US.
A young woman said she received messages from Ramos on Instagram before the attack despite not knowing him.
Eva Mireles was identified as the teacher shot dead by Ramos with her family speaking out about the horrific attack in a statement.
Do you have a story tip? Email: email@example.com.