Some are suggesting there may have been problems with the initial story that came out of the deadliest mass shooting in modern US history. And others are suggesting that the official time of events could be wrong.
While police have been clear about what they believe on the night of the attack, that story has changed in recent days. Below is an account of that timeline – and the questions that remain amid the reports.
More than a week after the attack, police have still not laid out a complete timeline of what happened that night. And as more details are revealed, what information there is appears to be contradictory and confusing.
That missing information has allowed conspiracy theorists to step in and suggest that something else happened that night that hasn't yet been made public.
Throughout the investigation into the attack, those strange inconsistencies have allowed people to seize on the mysterious parts of the story and suggest something is being hidden about the attack.
That confusion is partly because authorities have now changed the timeline of what happened last night. And in that new timeline – given a week after the events – there appear to be a number of strange gaps and inconsistencies.
They suggest – apparently entirely without basis – that there is something not being told about Jesus Campos, the security guard who is said to have first engaged with the gunman. There is no suggestion, proof or substantial reports that there was anything unusual about his behaviour – but he has now found himself at the middle of questions about the police response to the attack.
Internet detectives claim to have visited the man's house, for instance, and are poring through his online footprint in an attempt to make their theories stick. False reports have even attempted to blame him for the attack, reviving conspiracy theories about their being another shooter on the night of the attack, which have been entirely rejected by police.
There is absolutley nothing to suggest that Mr Campos was involved in the attack in any way beyond what the police have communicated: that he found the attacker, was shot by him, and then alerted the police.
But while the conspiracy theories appear to have no basis at all, a range of questions do remain about the events of that night – and it appears to be those questions that have led the attack to become such fertile ground for planting conspiracy theories.
According to the new timeline, two hotel employees called for help and said that gunman Stephen Paddock had been shooting inside the hallway of the hotel, and that one of those shots had hit an unarmed security guard in the leg. That barrage of bullets inside the hotel came several minutes before Paddock went on to shoot out of the window, killing 58 people and injuring almost 500 in the massacre.
Police didn't arrive at Paddock's hotel room until two minutes after the shooting started, according to authorities. That has led to concern about how long police took to arrive at the room – they got there at 10.17pm, 12 minutes after the shooting began at 10.05pm.
That delay was despite the fact that police now say there was six minutes between Paddock shot inside the hotel and when he began his shots into the crowd at the concert. And there was a full 18 minutes between the shooting of the security guard and the police's arrival in the room – despite the fact that staff were reported to have told authorities what room and what floor the shooter was in.
Questions have now arisen about whether police actually knew about that. If they didn't, why weren't they told? And if they did, what happened in those crucial minutes?
Here is an Associated Press run-down of what happened in those mysterious, crucial moments.
THE CHRONOLOGY OF THE SHOOTING HAS CHANGED
On Monday, Clark County Sheriff Joe Lombardo said Paddock shot and wounded the security guard outside his door and opened fire through his door around 9:59 p.m. — six minutes before shooting into the crowd.
That was a different account from the one police gave last week: that Paddock shot the guard, Jesus Campos, after unleashing his barrage of fire on the crowd.
The sheriff had previously hailed Campos as a "hero" whose arrival in the hallway may have led Paddock to stop firing. On Monday, Lombardo said he didn't know what prompted Paddock to end the gunfire and take his own life.
BULLETS WHIZZING DOWN THE HALLWAY
A hotel maintenance worker, Stephen Schuck, told NBC News on Wednesday that he told hotel dispatchers to call police and report that a gunman had opened fire in the hallway on the 32nd floor.
He had been called there to check out a report of a jammed fire door and made it about a third of the way down the hall when he heard gunshots. Schuck saw Campos, the security guard, peek out from an alcove and was told to take cover.
He described bullets whizzing past his head as he tried to flee the shooting.
"It was kind of relentless so I called over the radio what was going on," he said. "As soon as the shooting stopped we made our way down the hallway and took cover again and then the shooting started again."
Gunshots can be heard in the background as Schuck reported the shooting on his radio, telling a dispatcher: "Call the police, someone's firing a gun up here. Someone's firing a rifle on the 32nd floor down the hallway."
SECURITY GUARD IS SHOT
Campos had been dispatched to the 32nd floor before Schuck to respond to an alarm that signaled a door was open and heard an odd drilling sound, police have said. As he approached there was a series of single gunshots through the door, one of which hit him in the leg. At about the same time the maintenance worker arrived and Paddock fired more than 200 rounds through the door at Campos and Schuck.
As he was running away, Campos used his radio and possibly a hallway phone to call for help, Assistant Sheriff Tom Roberts confirmed to The Associated Press.
HOTEL QUESTIONS POLICE TIMELINE
Late Tuesday, a spokeswoman for Mandalay Bay questioned the latest timeline of events provided by police.
"We cannot be certain about the most recent timeline that has been communicated publically (sic), and we believe what is currently being expressed may not be accurate," said Debra DeShong, a spokeswoman for MGM Resorts International, which owns the Mandalay Bay hotel casino. The company's statement did not offer what it thinks was the correct timeline.
WHAT TYPICALLY HAPPENS WHEN THERE'S A SHOOTING AT A CASINO
A security officer in a casino-hotel the size of Mandalay Bay, with about 3,200 rooms, would typically report the shooting to an in-house dispatcher who would then call Las Vegas police, said Jim Tatonetti, an executive with Griffin Investigations, a Las Vegas company that provides security and surveillance information to casinos.
Tatonetti said they should have gotten word quickly about the shooting from the lead hotel security supervisor or they would hear the call from police dispatch.
"When you have law enforcement on property you defer to them," Tatonetti said, adding that hotel security officers would turn to their primary duty: guest safety. Officers would focus on evacuating and keeping guests away from dangerous areas.
A large casino in Las Vegas might have 50 or more security officers on a shift, Tatonetti said. Supervisors might be armed. Few on regular patrol have guns. Some might have emergency medical training.
WHAT WE STILL DON'T KNOW
It was unclear if the hotel relayed the reports of the hallway shooting or the gunman's location to the police. The Las Vegas Metropolitan Police Department hasn't responded to questions from The Associated Press about whether hotel security or anyone else in the hotel called 911 to report the gunfire. Police have not responded to questions about the hotel's statement or whether investigators stand behind the revised timeline released earlier in the week. A request for the 911 recordings was denied by police who said they were part of the ongoing investigation.
Additional reporting by Associated Press