New audio has emerged of security guard Jesus Campos reporting shots fired at the Mandalay Bay Resort during the October 1 massacre - but mystery still surrounds the exact timeline of the shooting.

Whether Campos was shot prior to the massacre or afterward remains unknown, as police have flip-flopped on the exact order of events, and MGM, which leaked the recording to ABC News, isn't saying when the recording took place.

Meanwhile, it's emerged that Campos - who has almost completely avoided speaking publicly about the shooting - has been kept out of the public eye by his employers, MGM.

The resort company is keeping the security guard in an unidentified hotel - leading to concerns that they may be trying to influence his testimony.

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Jesus Campos (left, with colleague Stephen Schuck on TV's Ellen) reported shots fired from the room (right) of Las Vegas killer Stephen Paddock, newly released audio reveals

Police have wavered on whether Paddock fired from two windows of MGM's Mandalay Bay Resort (pictured) before or after he shot Campos. MGM isn't saying when his call was made

In the days after the shooting, Sheriff Joseph Lombardo said that Campos had interrupted Paddock's 10-minute shooting spree.

Paddock saw Campos coming on cameras he'd set up, fired through the door of his sniper's nest, and injured the guard, Lombardo said. He claimed Paddock then stopped firing on crowds, just minutes before police arrived.

Days after that, however, a revised timeline was released that said Campos was fired on before Paddock started shooting at the crowds.

That left Lombardo unable to explain why Paddock fired for 10 minutes, then stopped firing for an hour before police burst into his room to find him dead of a self-inflicted gunshot wound.

Last week the timeline changed again, saying Campos was shot around the time that Paddock opened fire on the Route 91 Harvest country music festival.

In the audio obtained by ABC News, Campos can be heard saying, 'Hey, there's shots fired in, uh, [floor] 32 [room] 135.'

A crackling sound that could be gunfire from Paddock's rifles - some of which were modified to fire at auto speed - can be heard behind his voice.

ABC said the audio was supplied by MGM Resorts, which runs the Mandalay Bay Resort, but says the company won't say exactly when he called in the shooting.

That means Campos himself holds the key information about how the shooting occurred - and MGM are ensuring that he's not talking to anyone, the Las Vegas Review-Journal reported.

It has also emerged that Campos is staying in an unnamed property owned by MGM for free. The company says they're trying to protect their 'overwhelmed' employee from the media

Campos' only media appearance was in a softball interview with Ellen, in which he was not asked about the timeline confusion

The company has been paying the tab for Campos - who has avoided the media - to stay in one of their properties since he was identified on October 4, Campos' lawyer, Frank Flansburg III, said.

That's raised eyebrows for some.

'There's a suspicion that they are trying to shape his testimony and don't want him to provide information to the public about the incident,' Las Vegas attorney Will Kemp told the Review- Journal.

'Obviously, they want him to come out with a version of the timeline that's favorable to them,' said Kemp, who sued the MGM Grand after its deadly fire in 1980.

Another lawyer, Robert Eglet, whose company has surveyed the Mandalay Bay, said: 'Potentially, if they are influencing him in any way on his testimony, it's reasonable for people to suspect that they could be engaging and trying to control what his testimony or what his statement would be.'

But MGM Resorts' senior VP, Alan Feldman, said the company was just ensuring the well-being of one of its employees.

'When his name became public, Jesus was inundated with media coming to his home,' he said.

'Out of concern for our employee's safety, we provided a room for him. This was a very unusual circumstance, and our first and only concern was his safety.'

He added: 'He went from being a private citizen with no attention to suddenly being in the spotlight, and it was overwhelming while he was trying to recover from the tragedy.'

There is concern from some that MGM could influence Campos' testimony about the shooting (victims seen left) by Paddock (right). An MGM spokesperson said cops had visited Campos

He added that police had visited Campos and had also given the security guard the all-clear for a visit to Mexico, which he took shortly after the shooting, despite his injury.

Campos was born in Southern California and moved to Las Vegas as a teenager.

Chicago attorney Robert Clifford said he believed the MGM's explanation.

'Here's a man who just witnessed one of the most dramatic episodes a human being could witness, and they're trying to do the right thing to protect him from the hyper paparazzi-type environment that must be swirling around this tragedy,' he said.

Vegas defense attorney Thomas Pitaro agreed: 'As long as police are satisfied with the access they're getting to him, I don't see it as a problem.

'They're doing what they should be doing, taking care of their employee.'

Campos has only made one appearance in the media - in a softball interview with Ellen DeGeneres, who did not raise questions about the timeline.

Campos, a California native, also visited Mexico shortly after his shooting. According to the MGM spokesperson, police gave Campos permission to leave the country

On Wednesday the New York Times released a new version of the timeline, based on an analysis of the footage by experts.

They determined that Paddock began firing at the Route 91 Harvest festival concertgoers at 10.05pm, starting out with single shots.

Campos was shot a minute later - at 10.06pm - and not before the massacre began, as police had said earlier - they added.

Senior producer Malachy Brown, in a separate article about the timeline, explained how the study was produced: 'The process can be as simple as comparing a video with Google Street View to identify camera location or extracting file data with a smartphone app - or as difficult as analyzing each frame of a video and the amplitude and frequency of every second of audio.'