Nineteen police officers were in a hallway at a Texas primary school for more than 45 minutes before agents used a master key to open a door and confront the gunman responsible for the second-deadliest school shooting in a decade, authorities said on Friday.
The on-site commander believed the gunman was barricaded in a classroom at Robb Elementary School in Uvalde during Tuesday’s attack and that the children were not at risk, Texas Department of Public Safety Director Steven McCraw said at a news conference.
“Of course it was not the right decision. It was the wrong decision,” Mr McCraw said about officers not confronting the killer, 18-year-old Salvador Ramos, earlier in the incident.
"From what we know, we believe there should have been an entry as soon as you can," he added. "If I thought it would help, I'd apologise."
Police are facing severe criticism over their apparently botched response to the shooting that killed 19 children and two teachers on Tuesday.
Survivors, including children, were calling emergency services from the classroom long after Ramos had entered with an AR-15 semi-automatic-style rifle, while police officers standing in the hallway outside the room were waiting for backup and tactical gear, Mr McCraw said.
He said the on-scene commander believed at the time the suspect was barricaded alone in the classroom — and that the gunman's initial shooting spree had left no survivors.
However, Mr McCraw said, someone called 911 a number of times starting at 12.03pm, telling police in a whisper that there were several dead and that there were still “eight to nine” pupils alive.
One child told an emergency services operator: “Please send the police now.”
Officers did not go into the classroom until 12.50pm, Mr McCraw said.
US Border Patrol agents eventually used a master key to open the locked door of the classroom where they confronted and killed the gunman, he said.
A New York Times report on Friday said the Border Patrol tactical team was told to hold back from entering the school, after arriving on the scene shortly after 12pm.
"I'm not defending anything, but you go back in the timeline, there was a barrage, hundreds of rounds were pumped in in four minutes, OK, into those two classrooms," Mr McCraw said.
"Any firing afterwards was sporadic and it was at the door. So, the belief is that there may not be anybody living anymore and that the subject is now trying to keep law enforcement at bay or entice them to come in to suicide by contact."
The attack is the deadliest school shooting in the US since Sandy Hook, Connecticut, where 26 pupils and faculty members were killed.
It is the deadliest school shooting in Texan history.
Governor Greg Abbott held a press conference on Friday to discuss state benefits for anyone affected by the shooting and addressed a few questions about the police response.
"I was misled," he said, referring to a briefing he gave earlier with inaccurate information. "I am livid about what happened.
"Those are families whose lives have been destroyed. They need answers that are accurate and it is inexcusable that they may have suffered from any inaccurate information whatsoever."
Agencies contributed to this report