A mother of one of the 21 victims of last week's school shooting in Texas was told her daughter "might have lived" had the situation played out differently.

The fourth-grader, who was one of the 19 students shot dead at Robb Elementary in Uvalde on Tuesday, bled to death after she was shot in her kidney.

"Her child had been shot by one bullet through the back through the kidney area," State Sen. Ronald Gutierrez said on CNN's State of the Union on Sunday morning. "The first responder that they eventually talked to said that their child likely bled out. In that span of 30 or 40 minutes extra, that little girl might've lived."

If the police had breached the classroom sooner than they did, the girl might have received treatment sooner and survived her injuries.

AP News previously reported that police waited more than an hour to breach the classroom in which fourth graders were trapped with the shooter. The young students repeatedly called 911, including one child who pleased: "Please send the police now."

[[imagecaption|| Credit: Newscom / Alamy]]

A Texas official said at a news conference on Friday that the Uvalde police made the "wrong decision" by waiting so long to breach the classroom, where the attacker ultimately shot and killed 19 children and two teachers.

"From the benefit of hindsight, where I’m sitting now, of course it was not the right decision," Texas Department of Public Safety Director Steven McCraw said, per NPR. "It was the wrong decision, period."

"[The onsite commander] was convinced at that time that there was no more threat to the children and that the subject was barricaded and that they had time to organize with the proper equipment to go in," McCraw added.

Last Tuesday's massacre in the mostly Latino town of Uvalde was the deadliest shooting at a school in the US since 20 children and six adults were shot dead at Sandy Hook Elementary in Newtown, Connecticut, in December 2012.

The 18-year-old gunman, Salvador Ramos, entered Robb Elementary School at around 11:32 AM. He was armed with a handgun and an AR-15 semi-automatic rifle before "horrifically, incomprehensibly" opening fire, Texas Governor Greg Abbott said.

The teen also shot his grandmother and crashed his car near the school prior to entering the building. He was eventually shot dead by law enforcement officers. Nineteen children and two adults were killed in the attack.

Featured image credit: ZUMA Press, Inc. / Alamy

Mom of Texas shooting victim told daughter 'might've lived' had help come sooner