During a tense and at times emotional press conference held on Friday, Clark County Sheriff Joe Lombardo offered a third timeline of the Las Vegas massacre, saying there was no six-minute gap between when the gunman shot a hotel security guard and opened fire on concertgoers.

Lombardo, who is in charge of the Las Vegas Metropolitan Police Department, also revealed that Stephen Paddock deliberately fired on responding police officers, possibly to keep them at bay, but said there is no evidence that he was driven by ideology, or was affiliated with any group.

As of 8am on Friday, the number of injured victims was 546 but only 45 of them were still hospitalized, some in critical condition. The rest have been discharged.

A visibly shaken Sheriff Lombardo choked up talking about one of the victims, Metro Police officer Brady Cook, who he said suffered four gunshot wounds in the mass shooting but asked to return to work this morning.

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Shaken: Las Vegas Metropolitan Police Sheriff Joe Lombardo chokes up during Friday's press conference talking about officers wounded in the October 1 mass shooting

Lombardo broke down after mentioning that officer Brady Cook, who was wounded, asked to return to work Friday morning

According to the sheriff, it is believed that Paddock, 64, intentionally fired upon jet fuel tanks near McCarran Airport.

‘I have been advised there is a very low probably that aviation fuel could be ignited by gunfire,’ Lombardo stated.

Seeking to clear up the confusion surrounding the timeline of the events, which has been revised multiple times since the October 1 massacre, Lombrado said he continues to stand by the latest chronology, according to which the incident began unfolding at 9.59pm on October 1.

MGM Resorts International, which owns the Mandalay Bay, released a statement Thursday questioning that timeline because it suggested that hotel security guard Jesus Campos, who was shot and wounded by Paddock, may have waited up to six minutes to report the attack.

Hotel officials claimed it was no more than 40 seconds between the time Campos used his walkie talkie to call for help and Paddock opening fire from his arsenal of weapons on 20,000 concertgoers at the Route 91 Harvest Festival across the street.

On Friday, the sheriff said he was ‘very well aware of the MGM statement’ and that he was not in conflict with it.

Police say gunman Stephen Paddock (pictured) adjusted his fire to target police vehicles responding to the scene of the mass shooting

Paddock shot Mandalay Bay security guard Jesus Campos at around 10.05pm on the 32nd floor of the hotel, not 9.59pm, as it had been suggested earlier

Lombardo sought to clarify the timeline, saying that at 9.59pm, Jesus Campos encountered a barricaded stairwell door and had to ascend to another level in order to reach the 32nd floor where Paddock’s room was located.

NEW TIMELINE This is the revised timeline given out on Friday. 9:59pm: Campos approaches Paddock's room looking for an alarm going off at a door nearby - likely from the stairwell. He encounters a barricaded door and makes his way to 32nd floor. 10:05pm: Campos is shot and wounded in the leg. He radios and calls in incident as gunman opens fire on concert. 10:12pm: First two officers arrive on the 31st floor. 10:15pm: The last shots are fired from the suspect for reasons unknown. 10:17pm: The first two officers arrive on the 32nd floor from the 31st. 10:26-10:30pm: With Paddock quiet, eight more cops arrive and they decide to evacuate the rooms on the floor. 10:55pm: Eight officers arrive in the stairwell next to the suspect's room and find the door tampered with and a camera on a room service cart outside; they decide to hold off. 11:20pm: Paddock's room is breached and police enter the room to find him dead. Advertisement

According to the sheriff, the security guard was shot in the leg ‘closer to 10.05pm,’ at which time he radioed in shots fired and also called on his cellphone to report the incident.

Lombardo added that 10.05pm was also when ‘the majority of the fire started,’ referring to the shooting targeting the country music festival.

At 10.17pm - 12 minutes later - officers first arrived on the 32nd floor. The sheriff said that firing ‘had ceased’ by that point and Paddock killed himself with a shot to the head.

It is still unclear why he stop firing on the festival when he did, or what his motive was.

The sheriff said that Paddock’s brain has been sent to a special medical facility, where it will be subjected to microscopic analysis, after a preliminary evaluation revealed no visible abnormalities.

Lombardo’s latest version of events dovetails with that presented by Mandalay Bay officials on Thursday.

‘There is no conspiracy between the FBI, LVMPD and MGM,’ Lombardo said emphatically.

Security guard Jesus Campos disappeared Thursday night, just moments before he was set to speak to the press for the first time since the savage attack.

As of late Friday afternoon, the whereabouts of wounded Mandalay Bay staffer were unknown.

After conducting hundreds of interviews, reviewing digital media and 1,000 pieces of evidence, Sheriff Lombardo said police and the FBI have found ‘no signs of ideology or affiliation with any groups.’

Sheriff Lombardo said by the time police officers arrived outside Paddock's hotel room door, at 10.17pm, firing had ceased

Where is Jesus Campos? Las Vegas security guard disappears before he was set to speak to the media The Mandalay Bay security guard who was shot before gunman Stephen Paddock opened fired on concertgoers across the street from the hotel disappeared Thursday night, just moments before he was set to speak to the press for the first time since the savage attack. As of Friday afternoon, the whereabouts of Jesus Campos were unknown. DailyMail.com reached out for comment to David Hickey, president of the International Union, Security, Police and Fire Professionals of America that represent the guard, and were awaiting a response. According to the latest timeline provided by police detailing the events of October 1, Paddock sprayed 200 rounds into the hallway on the 32nd floor of Mandalay Bay, wounding Campos in the leg, just before he unleashed his barrage of bullets on the crowd attending the Route 91 Harvest Festival. Campos, who was unarmed, survived the shooting and was scheduled to sit down for five TV interviews Thursday night, including one on Fox News, but suddenly vanished. ABC News reporter Stephanie Wash tweeted Thursday, quoting the president of Campos' labor union: 'We were in a room & we came out & he was gone.' She followed up by writing that Campos' whereabouts were unknown. The security guard was supposed to be interviewed by Fox News' Sean Hannity, but the host tweeted on Thursday: 'He cancelled.' Advertisement

Earlier this week, lawyers had questioned why police and security weren’t able to stop Paddock sooner when authorities said six minutes passed between the bursts of gunfire.

Lombardo also pushed back against criticism of his office over whether more could have been done to stop the shooter.

'In the public space, the word incompetent has been brought forward. I am absolutely offended with that characterization,' he said.

As authorities seek answers, they are lacking one important investigative tool. There are no surveillance cameras in the hallways at the Mandalay Bay.

The FBI, which is leading the investigation, again pleaded for the public’s help.

'We continue to ask you if you have factual information in furtherance of this investigation, please call us. If you know something, say something,' FBI Special Agent in Charge Aaron Rouse said. 'Nothing will be overlooked. We have made significant progress,'

After paying tribute to his injured officers for their bravery, a choked-up Lombardo wrapped up the news conference without taking any questions from reporters.

'I want to thank you for letting me be your sheriff, and Vegas strong,' he said before walking out of the briefing room.