Three days after an 18-year-old gunman fatally shot 19 students and two teachers and wounded 17 others in a fourth-grade classroom at Robb Elementary School in Uvalde, Texas, big questions remain about how police responded to the murders, and FBI and other authorities are being called on to investigate.

In the aftermath of the shooting, Texas Gov. Greg Abbott praised law enforcement for “showing amazing courage,” but bystanders at the scene — some of them parents of victims — soon came forward to say that the police did not do enough, quickly enough. The Uvalde local police, and state police, have also given conflicting accounts of their actions while the shooter was in the school building.

The story got even murkier at a press conference on Friday, when Texas Department of Public Safety Director Steven McCraw acknowledged that officers made “the wrong decision” in approaching the school.

Police had thought they were dealing with someone who had barricaded himself in the school, not an active-shooter situation, McCraw said, and the on-scene commander, the chief of police of Uvalde schools, believed that “there were no kids at risk,” McCraw said.

“Of course, from the benefit of hindsight. … It was the wrong decision. Period,” McCraw said — a decision that appears to have led at least two students to call 911 while others lay dying or played dead.

There was a stark contrast between previous official statements, which described the police response as immediate, and Friday’s press conference in the face of mounting evidence to the contrary. But it was only the latest in a week of contradictions. Conflicting reports and erroneous information, even from officials, isn’t uncommon in the first hours after a shooting. But three days after the gunman entered Robb Elementary, the gaps in the narrative are proliferating, and many questions are still unanswered.

What happened when police entered the building? What happened during the 90 minutes between the gunman entering the school and police killing him? Did officers’ hesitation in entering the school cost children’s lives? Why was a Border Patrol tactical team told to stand back before approaching the gunman?

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The details that have so far emerged about what police did — and didn’t do — from 11:30 am to shortly after 1:30 pm paint a complicated and murky picture. At least some details suggest that police did not, in fact, try to stop the gunman as quickly as possible.

Here’s what we know — based on new disclosures from law enforcement, press reports, and witness accounts about how the police responded — and here’s why bystanders say there’s more to the story.

What we know about the timeline

The most detailed timeline of events so far comes from claims in law enforcement press conferences on Thursday and Friday.

At 11:28 am on Tuesday, the gunman crashed his grandmother’s pickup truck outside the school. (He had just shot his 66-year-old grandmother in the face. She survived and is in stable condition, according to Texas Department of Public Safety regional director Victor Escalon.)

When he got out of the vehicle holding his rifle and a bag (which officers now know held ammunition), he shot at two people who ran out from Hillcrest Memorial Funeral Home across the street. The two people were uninjured.

The gunman then jumped the fence outside the school and began shooting at the building from the parking lot.

Police received the first 911 call at 11:30 am. The caller informed them of the crash and that the driver had a gun.

Beginning at 11:33 am, the gunman fired more than 100 rounds. At 11:40 am, the shooter entered the west side of the school building.

This is where the official narratives start to contradict one another. On Wednesday, the police said that he encountered an armed school resource officer; on Thursday, Escalon said the gunman walked in unimpeded through an unlocked door to the building.

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At 11:35 am, police officers — including members of the Uvalde Police Department and the Independent School District Police Department, the school district’s designated police force — had entered the school. Half an hour later, there were a total of 19 officers in the school, McCraw said Friday.

The gunman locked himself in the classroom and continued firing.

The initial officers “received gunfire” and didn’t “make entry initially because of the gunfire they are receiving,” Escalon said, and would “take rounds,” then “move back, get cover.”

At the same time, officers called for additional resources, including tactical teams, specialty equipment, body armor, precision riflemen, and negotiators, and officers were evacuating students and teachers.

Agents from Border Patrol and Immigration and Customs Enforcement arrived around noon, much earlier than previously known, McCraw said on Friday. But they did not breach the classroom and kill the gunman until 12:50 pm, about 80 minutes after the shooter entered the school. Uvalde police officers kept them from going in, McCraw said, even though they had heard gunfire.

At 12:15 pm, a 911 call informed officials that about eight or nine students were still alive. Officials are still working to determine who among those children died or survived.

At 12:36, about an hour after police first entered, a child called 911. She was told to stay quiet.

At 12:47, she begged them to “please send the police now.”

The Border Patrol tactical team did not enter the classrooms until after that moment, McCraw explained. What the police were doing inside the school during the nearly 90 minutes after the gunman entered, why they delayed so long even while children called 911, and what happened to the “eight to nine students” who were still alive at 12:15 pm is still unclear.

The conflicting reports

The Friday press conference flatly contradicted previous accounts from law enforcement, reports that had, in many cases, already conflicted with one another.

On Wednesday, McCraw, the Texas Department of Public Safety director, said that an officer “engaged” the shooter. Yet officials reported on Thursday that there was no officer who confronted the gunman when he arrived.

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On Wednesday, McCraw said that Uvalde police officers arrived, immediately entered the school, “engaged the active shooter and continued to keep him pinned down in that location.” When a reporter asked how long officers engaged with the shooter, McCraw responded, “within 40 minutes or something, within an hour. I don’t want to give you a particular timeline,” then repeated that officers engaged “immediately.”

Police backtracked Thursday and said there were no officers on the scene when the gunman arrived. And McCraw’s press conference on Friday described an entirely different sequence of events, in which officers didn’t immediately enter, nor did they engage the shooter. The immediate, aggressive response depicted in earlier police press conferences didn’t happen.

Other reports from law enforcement raise more questions about what happened during those 90 minutes. Public Safety Department Lt. Chris Olivarez told the Today show on Wednesday that when officers arrived at the school they could hear gunshots ringing out from inside the building and he told CBS Mornings on Wednesday that they “could see the shooter.” The gunman had “barricaded himself inside” the classroom, he told Today, and was “​​shooting numerous children and teachers that were in that classroom, having no regard for human life.”

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According to Olivarez, police did try to enter the school but the gunman shot at them, and “there was no way they were able to make entry,” which prompted officers to begin breaking windows to help students escape, and to keep their “primary focus” on evacuating children.

Olivarez told CNN Thursday evening that officers who first responded waited for a tactical team to arrive because they could have been shot if they attempted to confront the gunman alone: “The active shooter situation, you want to stop the killing, you want to preserve life, but also one thing that — of course, the American people need to understand — that officers are making entry into this building. They do not know where the gunman is. They are hearing gunshots. They are receiving gunshots.”

He continued: “At that point, if they proceeded any further not knowing where the suspect was at, they could’ve been shot, they could’ve been killed, and that gunman would have had an opportunity to kill other people inside that school.”

One report noted that a student is thought to have bled to death in the hour it took officers to enter the classroom, leaving parents wondering whether she would still be alive had she been rushed to the hospital sooner.

Bystanders paint a fuller picture of what happened in those 90 minutes

The conflicting police accounts may partly be the result of how challenging it is to piece together a complicated and traumatic event, as Escalon claimed. “There’s a lot of information, a lot of moving parts. We have a lot of people involved in this investigation. … Our job is to report the facts and have those answers. We’re not there yet,” he said on Thursday.

But critics, including bystanders, claim the police accounts are conflicting because officers did not do their jobs.

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Bystanders at the scene said officers were just standing there. Angeli Rose Gomez told the Wall Street Journal that she drove to the school after hearing about the attack and witnessed police “just standing outside the fence. They weren’t going in there or running anywhere.” After pleading with officers to go inside, she said that federal marshals arrested her for interfering in an investigation.

One man, Juan Carranza, who lives across the street from the school, told the Associated Press that a woman yelled at officers standing outside the school repeatedly to “Go in there,” but the officers did not. Another, Javier Cazares, told the news service that “more could have been done”: his daughter, Jacklyn Cazares, was killed in the shooting, and when Javier Cazares arrived at the school, he tried to devise a plan to rush into the building since officers were still gathered outside.

Other parents were pinned to the ground, pepper sprayed, or tasered, said Gomez, who said she managed to run into the school and save her child after convincing the officers to uncuff her. When asked about these reports on Thursday, Escalon said, “I have heard that information, but we have not verified that yet.”

Videos posted to YouTube of the scene outside the school show officers holding parents back and pinning one to the ground, as others screamed to be let inside the school and urged officers to “Get your ass inside that building!” One officer tried to assure parents that they were taking care of it, that officers were actively removing children from the building, to which one woman replied, “Bullshit, he ain’t dead yet,” implying that the shooter was still firing.

The Washington Post reported that shots were still audible at 12:52 pm, according to radio recordings. At 1:06 pm, Uvalde police announced online that the shooting was over.

One fourth grader who survived the shooting after hiding underneath a table explained what happened when the police arrived in the classroom.

“When the cops came, the cop said: ‘Yell if you need help!’ And one of the persons in my class said ‘help.’ The guy overheard and he came in and shot her,” the boy said. “The cop barged into that classroom. The guy shot at the cop. And the cops started shooting.” The police got a student killed, according to the survivor’s story.

These details raise questions about the role of police officers in shootings, and they are reigniting debate about whether law enforcement and related safety measures keep schools and communities safe.

During the Parkland, Florida, school shooting in 2018, the only armed officer outside of the school stood outside and did nothing as a gunman murdered 17 students and injured 17 others. He was charged with counts of child neglect, culpable negligence and perjury; he could face the death penalty if convicted.

The Uvalde School District, which serves a town of about 16,000, had a detailed safety plan, featuring 21 “preventative security measures” that it has taken to bolster school safety, including employing four officers, staff who patrol door entrances, and employing trained professionals who assess threats, and monitor social media for threats.

The plan also included installing perimeter fencing and security cameras and supplying schools with portable metal detectors and radios for campus communication. Teachers were required to keep their classroom doors locked at all times. The district’s bullying and threat reporting system was supposed to catch concerning behavior early on. The school spent $450,000 on security and monitoring services in the 2019-20 fiscal year, up from $200,000 the year before, CNN reported. The Uvalde Police Department has previously touted its SWAT team on social media, but it is unclear whether that team responded to the shooting.

Despite these conflicting stories and a timeline that’s littered with gaps nearly two days after the massacre, officials continued to congratulate themselves on their response until the abrupt reversal at Friday’s press conference.

“If those officers weren’t there, if they did not maintain their presence, there is a good chance that gunman could have made it to other classrooms and commit more killings,” Olivarez said Thursday evening.

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