An investigator works in the 32nd floor suite of the Mandalay Bay Resort and Casino where a gunman opened fire on a concert crowd, killing 58 and wounding hundreds. (Gregory Bull/AP)

Note: This story has been updated.

One month after the Las Vegas mass shooting from the Mandalay Bay hotel, perhaps the biggest unresolved question is: Why did the police take so long to locate the shooter when the hotel staff knew exactly where he was?

That, in turn, raises a second question: Could a quicker response have stopped or disrupted the onslaught and saved lives?

For 10 minutes on Oct. 1, Stephen Paddock fired more than 1,000 shots into the crowd at the Route 91 Harvest music festival, killing 58 and wounding or causing injury to 564 more, according to Las Vegas Sheriff Joe Lombardo. But first, Paddock fired through his 32nd floor hotel room door, wounding Mandalay Bay security guard Jesus Campos at 10:05 p.m.. Campos promptly notified his supervisors of the incident.

In a gigantic hotel, Paddock had revealed his location before he ever started his attack.

At the same time, building engineer Stephen Schuck was also on the 32nd floor, and immediately radioed to his bosses, ““Call the police, someone’s firing a gun up here, someone’s firing a rifle on the 32nd floor down the hallway.” In less than a minute, Schuck reports on his radio, “Security is here,” and he can be heard advising them, “100 hallway, don’t go.”

Now there were two people reporting the location of the shooter at the outset of the incident.

Both MGM Resorts International, the owner of Mandalay Bay, and Lombardo have made statements about their response to the shooting. But the statements are contradictory, and both MGM and Lombardo have refused to clarify what happened.

MGM issued a statement on Oct. 12 which said that “Metro officers were together with armed Mandalay Bay security officers in the building when Campos first reported that shots were fired over the radio. These Metro officers and armed Mandalay Bay security officers immediately responded to the 32nd floor.”

But MGM would not say what time these officers arrived on the 32nd floor or what happened after they got there. Paddock began firing out the window within 40 seconds of shooting Campos, authorities have said.

Lombardo said in numerous press briefings that officers did not reach the 32nd floor until 10:17 p.m., 12 minutes after Paddock’s attack began. Paddock stopped firing at 10:15 p.m.

With the attack seemingly stopped, or at least paused, officers focused on evacuating the floor and didn’t break into Paddock’s room for another hour. By then, Paddock was dead.

Catherine Lombardo, a California lawyer who has filed a class-action lawsuit on behalf of the shooting victims, said she was skeptical of all the timelines offered so far, including those describing the response to the shooting. “It’s extremely important, and the story keeps changing,” said Lombardo, who is not related to the sheriff. She and other lawyers spent last week in Las Vegas examining the concert grounds and will return this week to visit the hotel’s 32nd floor. “We want answers. Period.”

In an interview aired Wednesday on KLAS-TV, Sheriff Lombardo was asked about the police response. “Well, the response time in my opinion was amazing,” he said. He agreed with the first part of MGM’s statement, saying that “we had two officers that were present at the Mandalay Bay handling another call for service. They become aware of a possible active shooter.”

Las Vegas Sheriff Joe Lombardo holds a media briefing at Las Vegas police headquarters. He has not commented on Mandalay Bay’s claim that police officers and security officers were on the 32nd floor during the shooting. (Steve Marcus/Las Vegas Sun via AP)

But he said that those officers had “no idea what floor it is,” despite the reports from Campos and Schuck on the 32nd floor. The sheriff said the officers “ascended up through the stairwell…and then they encountered the blocked doorway, similar to what Mr. Campos had described.

“So that was right around 10 minutes they were able to do that,” the sheriff said. “So, I mean, that’s pretty amazing in public safety time.”

Sheriff Lombardo added that “then our other officers that ascended via the elevator bank came out into the foyer or the hallway there, from the elevator bank, that was right around 12 minutes. But during that time, the suspect had stopped firing.”

Lombardo has declined to answer multiple inquiries about what communications his officers had with hotel security after the reports from Campos and Schuck.

Between 10:05 and 10:15 p.m., police officers at the concert and on the Las Vegas Strip who are pinned down by the gunfire can be heard on dispatch tapes pleading for someone to find the shooter. Lombardo told KLAS that he believed that Paddock stopped his attack because he thought “the wolf, meaning us the LVMPD, was at the door.”

But in 10 minutes, Paddock fired 12 bursts of bullets using automatic-style rifles, with pauses between each burst. The sheriff says his officers arrived only after the shooting stopped. But MGM’s report of an immediate response, combined with Schuck’s radio call that “security is here,” suggests that at least some armed personnel made it to the floor while the shooting was ongoing.

With an active shooter in the process of committing the largest mass killing in recent American history, the uncomfortable question arises: Could the Las Vegas and Mandalay Bay officers have tried to stop him?

To add some context, the city and private officers almost certainly carried only semiautomatic pistols, with up to 14-shot capacity and maybe some extra magazines on their belts, while Paddock was wielding high-powered rifles apparently modified to fire with automatic frequency.

The officers didn’t know how many shooters there might be. And they could see a wheeled cart in the hallway near Paddock’s suite, with wires trailing back under Paddock’s door. Those apparently enabled a camera to show him the hallway, but could also have appeared to the officers to be a booby trap. If they got close enough to see it.

Paddock had fired a first volley of shots through his door at 10:05 p.m., wounding Campos and causing Schuck to duck for cover. The New York Times, in a video compilation of footage recorded during the shooting, theorized that Paddock fired a second volley through his door at 10:10 p.m., based on the muted sound captured outside the hotel. This could have been Paddock seeing those first city and hotel officers on his floor. Lombardo has said Paddock fired 200 rounds into the hallway.

Also to be considered: After the 1999 Columbine shootings, and then again after the 2008 Mumbai attacks, first responders are no longer told to wait for backup. Police protocol is to go in immediately, find and neutralize the shooter.

Pete Blair is one of the foremost experts on active shooter training. As the executive director of the Advanced Law Enforcement Rapid Response Training Center at Texas State University, he has trained thousands of law enforcement officers in these situations. He cautioned, as the Las Vegas sheriff has, that the timeline of events hasn’t been conclusively established.

The first officers to arrive “have to make the assessment what to do,” based on the circumstances, Blair said. “We teach that the first priority is to stop the killing. But do they [Las Vegas police] have a policy? Do they allow such officers to confront active shooters?” Some departments require a certain number of officers before such a confrontation, Blair said.

“It really does come down to the read of the officers on the floor,” Blair said, “as to what they can accomplish. While they’re supposed to assume some risk, they’re not supposed to get themselves killed.” He said the officers should notify their supervisors of the situation, but if their communications are not solid, “it definitely warrants more caution.”

“It really does come down to the read of the officers on the floor,” Blair said, “as to what they can accomplish. While they’re supposed to assume some risk, they’re not supposed to get themselves killed.” He said the officers should notify their supervisors of the situation, but if their communications are not solid, “it definitely warrants more caution.”

David Gomez, a former FBI counterterrorism executive and Los Angeles police detective, said the first officers in such a situation have to ask themselves, “‘Do I kick the door? Do I wait for SWAT?’ I think the prudent thing for the officers is to wait for some direction. They have to ask, how much risk do they want to put themselves into? You don’t just go willy nilly into something like that without a plan. They don’t know if it’s one guy [shooting]. Is it five guys? Is he waiting for us to enter? Is there a better way tactically? They may have been armed, but I highly doubt they were carrying long weapons of the type you’d need.”

Mandalay Bay building engineer Stephen Schuck, left, and security guard Jesus Campos appear at a taping of “The Ellen DeGeneres Show” on Oct. 17. Both responded to a report of a malfunctioning fire door. Campos was shot and wounded by Stephen Paddock. They then alerted the hotel to the gunfire. (Michael Rozman/Warner Bros. via AP)

While Blair and Gomez counseled caution, others felt that the first responding officers needed to try to interrupt Paddock by any means necessary. They were also critical of MGM and Mandalay Bay for not being ready for such a situation in an age when mass shootings are, sadly, commonplace.

Tom Conley, head of a private security firm in Des Moines and counterterrorism instructor for the U.S. Department of Defense, wrote an article in Security magazine blistering Mandalay Bay for not stopping the attack. “I was confused how it was that the killer could have been allowed to keep shooting seemingly unhampered for 11 to 12 minutes. My first thought was, ‘Where the heck was hotel security’ while all this shooting was happening and while people were dying?”

After his article appeared, MGM released its statement indicating their security people were there. Conley said the hotel’s first mistake was sending an unarmed security guard to check the unsecured fire door. Conley said Campos was a contractor from a “yellow T-shirt” concert event-type security company, not a full-time Mandalay Bay employee. He said there also didn’t appear to be any way for Mandalay Bay to communicate its situation to the concert security across the street.

Conley said MGM should have had an armed response team ready to roll in such a situation, that they would have rushed to the 32nd floor and carefully moved toward the shooter’s suite. “If the person starts firing through the door,” Conley said, “you fire back and the problem’s eliminated. For them [MGM] to be somehow taken off guard or surprised by this is really criminal.” He said if Campos had been armed, “he could have immediately returned fire. He only has to keep the guy busy until backup arrives. If they had trained professionals, where the hell were they on the 32nd floor when Campos was shot? The police respond and they don’t know what floor to go to? ” He credited hotel and casino owner Steve Wynn with taking aggressive security steps at his properties that other Las Vegas hotels have not.

Lawyers representing victims of the shooting expressed similar sentiments. “They know this kind of event is possible,” said attorney Richard Bridgford, representing the family of Andrea Castilla. “It’s like earthquakes, they’re inevitable and buildings are earthquake-proofed. These shootings are the lead story for the last year and a half. They knew the ‘earthquake’ was going to occur. They need to have a security protocol designed to stop something like this from occurring.”

Here is the full statement issued by MGM Resorts International on Oct. 12:

Although we prefer not to comment on the details of the investigation, we are issuing this statement to correct some of the misinformation that has been reported. The 9:59 p.m. PDT time was derived from a Mandalay Bay report manually created after the fact without the benefit of information we now have. We are now confident that the time stated in this report is not accurate. We know that shots were being fired at the festival lot at the same time as, or within 40 seconds after, the time Jesus Campos first reported that shots were fired over the radio. Metro officers were together with armed Mandalay Bay security officers in the building when Campos first reported that shots were fired over the radio. These Metro officers and armed Mandalay Bay security officers immediately responded to the 32nd floor. We will continue to work with law enforcement as we have from the first moments of this tragedy as they work toward developing an accurate timeline.