Eleven days after a gunman opened fire into a crowd at a country music festival in Las Vegas, killing 58 and injuring hundreds, investigators are still searching for answers.
Federal and local agencies have worked around the clock collecting evidence, delving into the gunman's life and interviewing those close to him -- but the gunman's motive and why he stopped shooting when he did remain a mystery.
Clark County Sheriff Joseph Lombardo asked the public for patience, saying authorities are trying to "draw the most accurate picture" of how the shooting unfolded.
"There's more than 20,000 moving parts associated with this investigation and it takes time," he 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 six minutes after the hotel security guard was shot?
In a new timeline of events released Monday, police said that Paddock shot Jesus Campos, a hotel security guard, six minutes before the gunman began firing into the crowd at the Route 91 Harvest Festival from his 32nd floor room at the Mandalay Bay Resort and Casino.
Paddock opened fire on the crowd at around 10:05 p.m. and unleashed bullets on concertgoers for about 10 minutes. The police didn't get to the 32nd floor until 10:17 p.m., and they didn't breach the room until 11:20 p.m., after a SWAT team arrived with explosive charges, Lombardo said.
Lombardo said that Campos, upon being shot, immediately notified security of his situation, and his action helped identify the location of the suspect. In addition, Campos prevented a maintenance worker on the same floor from suffering injuries, the sheriff said.
Police did not know Campos was shot until they met him in the hallway of the 32nd floor after getting off the elevator, Lombardo said.
What exactly happened in the six minutes between Campos' getting shot and the mass shooting on concertgoers? Who did the security guard alert, and what was their response? Why did it take officers 18 minutes from that point to reach the gunman's floor?
A new lawsuit accuses MGM Resorts International, which owns the Mandalay Bay and the venue where the concert took place, of failing to respond in a timely manner after Campos was shot.
In a statement Tuesday, MGM Resorts, which owns the Mandalay Bay, said: "We cannot be certain about the most recent timeline that has been communicated publicly, and we believe what is currently being expressed may not be accurate."
Is the new timeline of events correct?
Lombardo told KLAS that the timeline could change again. "Nobody's trying to be nefarious. Nobody's trying to hide anything. What we want to do is draw the most accurate picture we can," Lombardo said. "And I'm telling you right now, today, that that timeline might change again. ... It's human factor involved."
A law enforcement source close to the investigation disputed the MGM statement. "Our timeline is pretty accurate with all the facts known," the source said Tuesday.
Why did Paddock stop shooting after 10 minutes?
Police initially thought that Campos approached Paddock's door after the massacre had begun, and that Campos distracted him from firing into the crowd. Authorities had said that, after firing several rounds through his hotel room door at the guard, Paddock didn't fire any more shots out the window.
But with the disclosure that Campos was shot before Paddock began his rampage, it's unclear why he stopped after shooting for ten minutes.
By the time SWAT officers used an explosive to breach the door to Paddock's suite, they discovered him dead on the floor, apparently of a self-inflicted gunshot wound.
How could he meticulously plan this kind of attack without anyone noticing?
Over the course of several days, Paddock had brought guns and ammunition to his hotel suite. He had 23 weapons in his room and more than 50 pounds of explosives and 1,600 rounds of ammunition in his car in the hotel parking lot, police said. Twelve of the 23 firearms found in the hotel suite had bump stocks -- legal accessories for semi-automatic rifles that allow a shooter to fire bullets more rapidly.
In addition to the arsenal of weapons in Paddock's room, authorities found a handwritten note that contained calculations pertaining to the distance and trajectory from his 32nd-floor window to the crowd of concertgoers he targeted below, according to a law enforcement source with knowledge of the investigation.
Investigators said Paddock acted alone, and Lombardo said they have found "no evidence to show there was a second shooter."
The sheriff said authorities have received 200 accounts of Paddock traveling throughout Las Vegas, and that he "has never been seen with anyone else."
Speaking through her attorney, Paddock's live-in girlfriend Marilou Danley said that it "never occurred to me in any way whatsoever that he was planning violence against anyone."
What was he planning to do with the explosives in his car?
Investigators found that Paddock had "personal protection equipment with him," Lombardo told reporters Monday, leading them to believe that his plans didn't end with the mass shooting.
"We know he attempted to shoot at fuel tanks, we know he had personal protection equipment in the room, the car in the parking garage contained binary explosives, so 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," he said.
Why did he do it?
Authorities have received more than 1,000 leads and tips but still have no credible information about Paddock's motive.
Lombardo admitted that he was "frustrated" by the speed of the investigation in answering those questions.
"It isn't because nobody is not doing their job," he said. "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."
"As I've said from day one, we want to figure out why -- the why to this and we'd like to know the motive," Lombardo said. "That is our most important goal -- to prevent any further action associated with another individual who is contemplating this or what exactly went in the suspect's mind to enable him to pull off such a complicated event."
Nothing revealed about Paddock's life so far appears to provide any clues as to why he would have meticulously planned and carried out mass murder. The 64-year-old retired accountant had no apparent political or religious affiliations, his brother told reporters last week. He was known to stay up all night gambling.
Paddock would wager up to a million dollars a night, but wandered around glitzy Las Vegas 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 too much, according to a court deposition obtained exclusively by CNN that was part of a 2013 civil lawsuit against the Cosmopolitan Hotel.
He had no criminal record and did not raise any red flags while purchasing an arsenal of weapons.
Lombardo said the FBI was still evaluating Paddock's mental state.
"Currently, we do not believe there is one particular event in the suspect's life for us to key on," the sheriff had said. "We believe he decided to take the lives he did and he had a very purposeful plan that he carried out."
In the 2013 deposition, Paddock said he had no mental issues and no history of addiction.
Over the years, he owned apartments and houses in Nevada, Florida and California. Most recently, he lived in a retiree community about 80 miles of northeast of Las Vegas in Mesquite, Nevada.
He sought privacy and kept a low profile. Some of his neighbors rarely saw him.
Before checking into the Mandalay Bay days before the massacre, Paddock rented a room at a Las Vegas condo complex that overlooked the September 22-24 Life is Beautiful music festival.