(CNN) Despite running down more than 1,000 leads in the Las Vegas shooting investigation, authorities say they are struggling to determine why Stephen Paddock fired on a packed crowd of concertgoers, killing 58 people and wounding hundreds more.

A frustrated Kevin McMahill, the undersheriff at the Las Vegas Metropolitan Police Department, asked the public to avoid the constant rumor and speculation as to Paddock's motives, which he said were understandable but unhelpful.

"I get it," McMahill said. "We all want answers."

Indeed, in the week since the worst mass shooting in modern US history, there has been an intense focus on figuring out the shooter's motivation.

But why, exactly? Paddock himself is dead of a self-inflicted gunshot wound. Police are looking to find out if anyone knew of his plans ahead of time, but they have said he acted alone. There will be no criminal case against him. Learning his motivation won't bring back the dead or help heal the nearly 500 wounded.

Does his motivation even matter? Why do we care so much about the motives of mass shooters?

The answer, according to experts in profiling mass shooters, is that we dig into the motive of mass killings to try to prevent future attacks, adjust policy and -- perhaps most of all -- satisfy our own human curiosity.

"Everybody is talking about this. Everybody is asking 'Why'd he do it? What's the reason?'" said Jeffrey Simon, a visiting lecturer at the University of California, Los Angeles, and the author of " Lone Wolf Terrorism: Understanding the Growing Threat ."

"It's just human nature to speculate and want to know why something occurred."

Lessons learned

People walk by crosses placed near Las Vegas' famous sign on Thursday.

For Mary Ellen O'Toole, a former senior FBI profiler and author of "The School Shooter: A Threat Assessment Perspective," understanding a mass killer's motives can help stop future attacks.

"I like to think of these things as education," she said.

The general public has a misunderstanding of how these mass shooters radicalize, she said. In general, they don't suddenly "snap." Instead, they slowly radicalize to the point where their brains begin to see other humans as objects and just a means to a desired end.

Elliot Rodger, who killed six people at the University of California, Santa Barbara, in 2014, had written a lengthy manifesto describing plans to kill "beautiful girls" and "popular people" after years of rejection and jealousy.

The 22-year-old Rodger fatally stabbed his three roommates before shooting dead two women outside a sorority house and another man inside a deli. He wounded 13 others during his shooting spree before killing himself.

If we understand that end goal -- the motive -- then we can better understand how the process of radicalization happened and whether any groups or causes contributed to that. That may help the public better predict who might be at risk for radicalizing and prevent future attacks, O'Toole said.

"I find that this is a teachable moment and we don't want to lose that opportunity," she said.

Policy changes

The killer's motivation can also lead to policy changes, taking on that issue on a local, state or national level.

For example, Dylann Roof, motivated by white supremacist beliefs, killed nine people in a historically black church in Charleston in 2015.

"I think it's part of human nature," said Michael Stone, a professor of clinical psychiatry at Columbia University who has studied hundreds of mass killings.

"When something terrible happens, you want to know what were the factors that led up to it and whether there's something about it that we could spot beforehand. Maybe we could head trouble off at the pass."

In Orlando, a gunman's targeted killing of 49 people at Pulse, a gay nightclub, led to much stronger support for the LGBTQ community, local lawmakers have said

"You always have lessons learned after any kind of incident such as this, whether terrorist-related or not terrorist-related," Simon said.

'Part of human nature'

Photos: Mass shooting at Las Vegas music festival Debris is scattered on the ground Monday, October 2, at the site of a country music festival held this past weekend in Las Vegas. Dozens of people were killed and hundreds were injured Sunday when a gunman opened fire on the crowd. Police said the gunman fired from the Mandalay Bay hotel, several hundred feet southwest of the concert grounds. It is the deadliest mass shooting in modern US history. Hide Caption 1 of 30 Photos: Mass shooting at Las Vegas music festival Broken windows of the Mandalay Bay are seen early in Las Vegas on Monday. Police said the gunman fired on the crowd from the 32nd floor of the hotel. Hide Caption 2 of 30 Photos: Mass shooting at Las Vegas music festival People cross a street near the Las Vegas Strip just after sunrise on Monday. Thousands were attending the music festival, Route 91 Harvest, when the shooting started. Hide Caption 3 of 30 Photos: Mass shooting at Las Vegas music festival People embrace outside the Thomas & Mack Center after the shooting. Hide Caption 4 of 30 Photos: Mass shooting at Las Vegas music festival Police arrive at the Sands Corporation plane hangar where some people ran to safety after the shooting. Hide Caption 5 of 30 Photos: Mass shooting at Las Vegas music festival A woman cries while hiding inside the Sands Corporation plane hangar. Hide Caption 6 of 30 Photos: Mass shooting at Las Vegas music festival Concertgoers dive over a fence to take cover from gunfire on Sunday night. Hide Caption 7 of 30 Photos: Mass shooting at Las Vegas music festival Police take position outside the Mandalay Bay. Hide Caption 8 of 30 Photos: Mass shooting at Las Vegas music festival A man lays on top of a woman as others flee the festival grounds. The woman reportedly got up from the scene. Hide Caption 9 of 30 Photos: Mass shooting at Las Vegas music festival Hide Caption 10 of 30 Photos: Mass shooting at Las Vegas music festival People are seen on the ground after the gunman opened fire. Hide Caption 11 of 30 Photos: Mass shooting at Las Vegas music festival People run from the festival grounds. Hide Caption 12 of 30 Photos: Mass shooting at Las Vegas music festival A woman is moved outside the Las Vegas Tropicana resort. Multiple victims were being transported to hospitals in the aftermath of the shooting. Hide Caption 13 of 30 Photos: Mass shooting at Las Vegas music festival People are searched by police at the Tropicana. Hide Caption 14 of 30 Photos: Mass shooting at Las Vegas music festival An ambulance leaves the intersection of Las Vegas Boulevard and Tropicana Avenue. Hide Caption 15 of 30 Photos: Mass shooting at Las Vegas music festival A man in a wheelchair is evacuated from the festival after gunfire was heard. Hide Caption 16 of 30 Photos: Mass shooting at Las Vegas music festival Victims of the shooting are tended to in the street. Hide Caption 17 of 30 Photos: Mass shooting at Las Vegas music festival Concertgoers help an injured person at the scene. Hide Caption 18 of 30 Photos: Mass shooting at Las Vegas music festival People gather around a victim outside the festival grounds. Hide Caption 19 of 30 Photos: Mass shooting at Las Vegas music festival A couple huddles after shots rang out at the festival. Hide Caption 20 of 30 Photos: Mass shooting at Las Vegas music festival An injured woman is helped at the Tropicana. Hide Caption 21 of 30 Photos: Mass shooting at Las Vegas music festival Police and emergency responders gather at the intersection of Las Vegas Boulevard and Tropicana Avenue. Hide Caption 22 of 30 Photos: Mass shooting at Las Vegas music festival A police officer takes position behind a truck. Hide Caption 23 of 30 Photos: Mass shooting at Las Vegas music festival A crowd takes cover at the festival grounds. Hide Caption 24 of 30 Photos: Mass shooting at Las Vegas music festival Police officers advise people to take cover in the wake of the shooting. Hide Caption 25 of 30 Photos: Mass shooting at Las Vegas music festival People tend to a victim at the festival grounds. Hide Caption 26 of 30 Photos: Mass shooting at Las Vegas music festival Police stand at the scene of the shooting. Hide Caption 27 of 30 Photos: Mass shooting at Las Vegas music festival A woman sits on a curb at the scene of the shooting. Hide Caption 28 of 30 Photos: Mass shooting at Las Vegas music festival Police are deployed to the scene. Hide Caption 29 of 30 Photos: Mass shooting at Las Vegas music festival A man makes a phone call as people run from the festival grounds. Hide Caption 30 of 30

But there's also an essential human component to knowing a shooter's motivation. Stone, who wrote the book "The Anatomy of Evil," which explores the motivations and mindsets of the world's most prominent killers, said there's a "fascination" with such people.

"It's very hard to escape the fascination with these mass killers and mass murderers, and also the wish to have answers to what prompts some of these people to do these kinds of things," he said.

In general, mass killers, almost all of whom are young men, are motivated by some combination of paranoia and mental illness or financial and social problems, he said. A disgruntled recently fired worker, perhaps, or a jilted lover.

Paddock, though, doesn't seem to fit that type. He was a 64-year-old retired accountant with a girlfriend and plenty of money to spend. Investigators said they hadn't learned anything in his social life, finances or political beliefs that explained his path to radicalization.

"He doesn't fit into the major categories," Stone said. "Because Paddock doesn't fit in, he's all the more intriguing. So people are pounding on the table, 'We have to figure this guy out.'"

The sheer scale of the Las Vegas shooting, with such a large number of casualties, also makes these questions particularly relevant. Not knowing why it happened would leave many grieving families with lingering questions.

"In the end, (the motive) doesn't change anything in terms of the impact it has had on the poor people who died, who've been injured, their loved ones," Simon said. "But they may also want some type of closure as to why in the world did this occur."

Undersheriff McMahill said law enforcement will continue to dig into Paddock's background to learn more. O'Toole said she believes investigators should expend every effort to uncover his motivation.

"This was too horrible a crime, too extraordinary a crime to not to close the books (on)," O'Toole said. "(We are) obligated to the country, obligated to the citizens of Las Vegas, obligated to the families to understand why this happened."