The owners of the Las Vegas hotel where a gunman opened fire last week disputed on Thursday the police account of how part of the shooting unfolded, casting further doubt on what happened before and during the massacre.

In the days since Stephen Paddock opened fire from his 32nd-floor suite at the Mandalay Bay Resort and Casino, killing 58 people at a country music festival and injuring hundreds more before shooting himself, mystery has surrounded his motivations and planning.

But more recently, uncertainty has also grown regarding the law enforcement response and precisely what unfolded inside the hotel the night of Paddock's rampage Oct. 1, when the first gunshots were fired and why police and the hotel's owners have been unable to agree on basic facts about the timeline.

Police fueled this confusion when they said Monday that, contrary to an earlier timeline, Paddock fired at a hotel security guard six minutes before the massacre began. After reporting this six-minute gap, Joseph Lombardo, the Las Vegas sheriff, said police who responded to the 32nd floor did not know a guard had been shot.

This raised questions about whether the information was relayed to police officers, who searched the hotel for a gunman after Paddock began raining bullets on the music festival. MGM Resorts International, which owns the Mandalay Bay, had said this revised police timeline "may not be accurate" but they and police declined to answer repeated questions about what happened during the critical minutes before and during the shooting.

In a statement released Thursday, MGM Resorts said the specific time reported by Lombardo was incorrect and that Jesus Campos, the hotel guard, called in that shots had been fired within a minute of the gunman firing out his window. MGM also said Las Vegas officers were already with hotel security when Campos' call came, suggesting there was no lag in alerting police.

"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," MGM said in the statement, released by a public relations firm. "Metro officers were together with armed Mandalay Bay security officers in the building when Campos first reported that shots were fired over the radio."

The Las Vegas police did not immediately respond to a message seeking comment Thursday about the MGM statement.

Lombardo had said that Campos was shot at 9:59 p.m., while Paddock began firing down at the festival at 10:05 p.m. According to police, Paddock fired until 10:15 p.m.

MGM said that the 9:59 p.m. time offered by Lombardo was incorrect and "derived from a Mandalay Bay report manually created after the fact without the benefit of information we now have."

However, the MGM statement raises further questions about what happened in the hotel Sunday night. The statement said the police and security officers "immediately responded to the 32nd floor," though Lombardo had said that police did not get there until 10:17 p.m., which was 12 minutes after the gunfire began.

A spokeswoman for MGM did not immediately respond to a request for more information regarding what time Campos was shot, when the first shots were fired into the crowd and when officers arrived on the 32nd floor. Lombardo, who has attributed the shifts in the timeline to the developing investigation and a desire to be transparent, warned Wednesday that the timetable could shift again.

"Nobody's trying to be nefarious, nobody's trying to hide anything, and what we want to do is draw the most accurate picture we can," he said in a television interview Wednesday. "I'm telling you right now, today, that that timeline might change again."

Lombardo said during the interview that the timeline could shift again due to the "human factor," explaining that it was possible that the time of the first shots was written down incorrectly.

At the news briefing Monday, where he said Campos was shot at 9:59 p.m., Lombardo had said the guard "immediately" notified hotel security. He also said that police discovered that a guard was shot when they met him in the hallway after getting off the elevator.

MGM's statement also leaves uncertain whether the information about the shooting was relayed more widely to police officers. Police had said that during the shooting rampage, two officers searching on the 31st floor heard gunfire above them. According to this earlier timeline, police said that the officers arrived on the 32nd floor at 10:17 p.m. and, one minute later, relayed that a guard had been shot and identified the shooter's room.