The gunman's motive, the timeline of the shooting and why he stopped shooting -- these are among the wealth of unanswered questions that persist after 11 days of investigation into the Las Vegas music festival massacre.
The lack of answers, especially about the timeline, seems all the more curious when, it would appear, that many moments in the shooter's days-long preparation -- and the actual assault -- were captured by hotel video surveillance or by cameras the gunman himself installed in his suite and hallway.
Clark County Sheriff Joseph Lombardo has asked the public for patience, saying authorities are trying to "draw the most accurate picture" of how the shooting unfolded.
Federal and local agencies continue collecting evidence, delving into the gunman's life and interviewing those close to him.
"There's more than 20,000 moving parts associated with this investigation and it takes time," the sheriff told CNN affiliate KLAS on Wednesday.
Here's what we still don't know about the deadliest mass shooting in modern US history.
What happened in the 6 minutes after the hotel security guard was shot?
In a new timeline of events, police say Stephen Paddock shot security guard Jesus Campos six minutes before the gunman opened fire on the Route 91 Harvest music festival from his room at the Mandalay Bay Resort and Casino.
An open door to a room near Paddock's suite had set off an alarm, prompting Campos to respond.
Paddock opened fire at 10:05 p.m. and unleashed bullets on concertgoers for about 10 minutes. The police didn't get to Paddock's 32nd-floor suite until 10:17 p.m. They didn't breach the room until 11:20 p.m., after a SWAT team arrived with explosive charges, Lombardo said.
Lombardo said Campos, upon being shot, notified security, and his action helped pinpoint the suspect's location.
Police didn't know Campos was shot until they met him on the 32nd floor, Lombardo said.
It's still unclear who Campos initially contacted and what happened in the six minutes between Campos being shot and Paddock opening fire on the festival. Also fuzzy: Why did it take 18 minutes for officers to reach the 32nd floor?
A lawsuit filed by shooting victim Paige Gasper accuses MGM Resorts International, which owns the Mandalay Bay and the festival venue, of failing to respond in a timely manner after Campos was shot.
MGM has said it feels the timeline provided by police "may not be accurate." On Thursday, the company issued a statement saying it would respond to Gasper's allegations "through the appropriate legal channels."
"As our company and city work through the healing process, our primary focus and concern is taking actions to support the victims and their families, our guests and employees and cooperating with law enforcement," it said.
Is the new timeline of events correct?
Lombardo told KLAS the timeline is not static.
"Nobody's trying to hide anything. What we want to do is draw the most accurate picture we can," Lombardo said. "That timeline might change again."
Responding to MGM, a law enforcement source close to the investigation said police stand by the timeline, calling it "pretty accurate with all the facts known."
Why did Paddock stop shooting after 10 minutes?
Police initially said Campos distracted Paddock and that Paddock quit firing out the window after shooting Campos.
Now, police say Campos was shot before Paddock's rampage began. It's unclear why Paddock stopped shooting into the festival crowd after 10 minutes.
When SWAT officers breached Paddock's door, they discovered the gunman dead, apparently of a self-inflicted gunshot wound.
How could he meticulously plan this kind of attack without anyone noticing?
Over several days, Paddock took guns and ammunition to his hotel suite. He had 23 weapons in his room. In his car were more than 50 pounds of explosives and 1,600 rounds of ammunition, police said. Twelve of the firearms had bump stocks -- legal accessories for rifles that enable them to be fired more rapidly.
Authorities also found a note containing calculations on distance and trajectory to the concertgoers below, according to a law enforcement source.
Lombardo said they have found "no evidence to show there was a second shooter."
Authorities have received 200 accounts of Paddock traveling around Las Vegas, and that he "has never been seen with anyone else," the sheriff said.
Through her attorney, Paddock's girlfriend, Marilou Danley, said it "never occurred to me in any way whatsoever that he was planning violence."
What was he planning to do with the explosives in his car?
Investigators learned Paddock had "personal protection equipment with him," Lombardo told reporters Monday, leading authorities to believe he planned more than a mass shooting.
"We know he attempted to shoot at fuel tanks," Lombardo said. "I would be comfortable saying, depending on the splash he made during the shooting, it would enable first responders to draw their attention to other locations, which would allow Paddock to just leave the hotel."
Why did he do it?
Authorities have received more than 1,000 tips but still have no credible information on Paddock's motive.
Lombardo admitted the slow speed of the investigation frustrated him.
"It's because this individual purposely hid his actions leading up to this event and it is difficult for us to find the answers to those actions," he said.
Nothing about Paddock's life provides clues as to why he would have meticulously planned and perpetrated mass murder. The 64-year-old retired accountant had no apparent political or religious affiliations, one of his brothers said.
Paddock would wager up to $1 million a night but wandered around casinos in sweatpants and flip-flops. He carried his own drink into the high rollers' area because he didn't want to tip the waitresses much, according to a deposition obtained exclusively by CNN that was part of a 2013 civil lawsuit Paddock brought against the Cosmopolitan Hotel over a fall.
He had no criminal record. His purchase of an arsenal raised no red flags.
"Currently, we do not believe there is one particular event in the suspect's life for us to key on," the sheriff said.
In the 2013 deposition, Paddock said he had no mental issues or addictions.
Over the years, he owned apartments and houses in Nevada, Florida and California. Most recently, he lived in a retiree community in Mesquite, Nevada, northeast of Las Vegas.
He kept a low profile. Some neighbors rarely saw him.
In September, Paddock rented a room at a Las Vegas condo complex that overlooked the Life Is Beautiful music festival.
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