A girl saw her teacher killed in the Texas shooting but reportedly survived by lying on one of her classmates and smearing the girl's blood on herself to "play dead".
Miah Cerrillo's family have been describing the terrifying ordeal suffered by the 11-year-old, who has been left with bullet fragments in her body and singed hair from the gunfire.
Nineteen children and two teachers were murdered in Tuesday's atrocity.
Her father told the Washington Post that Miah witnessed teacher Eva Mireles being shot and the phone fall from her hand. Miguel Cerrillo said his daughter grabbed the handset and called 911.
In a bid to survive, she lay on top of a classmate who had been shot so that they both looked dead.
"Miah got some blood and put it on herself so she could pretend she was dead," her aunt Blanca Rivera told local TV station NBC DFW.
"It's too much for me to play that scene over and over again, but that's what my sister-in-law said is that she saw her friend full of blood and she got blood and put it on herself."
Miah's mother and father were among terrified parents who gathered outside the Uvalde school as the gunman was holed up inside.
Mr Cerrillo said he eventually saw his blood-soaked daughter and another child being carried out by an officer. She was taken to hospital with bullet fragments in her neck and back but has been discharged.
Miah said the girl she lay on was breathing but died before help arrived, her father told the Washington Post.
The trauma is now starting to dawn on the fourth-grade pupil.
Her aunt told NBC DFW: "Around midnight, my sister-in-law called me and she was just crying like, 'I think it just hit Miah. I think everything came to reality. We're home, and she's just crying and having a panic attack'."
It comes as criticism grows of how long it took law enforcement to enter the building, with officials saying it was up to an hour before a special Border Patrol team killed the gunman.
Some of the parents had to be restrained after saying they wanted to enter the school themselves to take action.
Javier Cazares, whose daughter Jacklyn was killed in the attack, said he raised the idea of entering the school with other bystanders.
"Let's just rush in because the cops aren't doing anything like they are supposed to," he said. "More could have been done."
"They [police] were unprepared," he added.
The hour-long interval before the special tactical team shot dead Salvador Ramos, 18, appears contrary to the approach of many law enforcement agencies to confront school gunmen as soon as possible.
He also managed to enter through an unlocked rear door, Texas Department of Public Safety (DPS) spokesman Victor Escalon said on Thursday.
A student told Reuters that some doors were unlocked to allow parents to come and go for an awards ceremony,
Mr Escalon said earlier reports that Ramos was initially confronted by an armed school-based police officer were incorrect.
He said two officers had instead entered the school four minutes after the gunman, but took cover after he fired at them. Ramos was then able to barricade himself in a classroom where he killed his victims.