The high-stakes gambler who carried out the deadliest mass shooting in modern America, killing 60 and injuring hundreds more in Las Vegas, was apparently angry over how the casinos were treating him despite his high-roller status, according to a fellow gambler.

An FBI interview with the gunman’s fellow gambler is detailed in hundreds of pages of documents made public this week. The gambler, whose name is redacted in the documents, said he believed the stress could have easily caused gunman Stephen Paddock “to snap.” Paddock, 64, was a video poker player who relied on gambling as his main source of income.

The revelation comes years after the FBI in Las Vegas and the local police department concluded their investigations without a definitive motive, although both agencies said Paddock burned through more than $1.5 million, became obsessed with guns, and distanced himself from his girlfriend and family in the months leading up to the massacre.

In a statement Thursday, Las Vegas police defended their inconclusive findings and dismissed the importance of the documents released this week in response to an open-records request from the Wall Street Journal.

“We were unable to determine a motive for the shooter,” the statement said. “Speculating on a motive causes more harm to the hundreds of people who were victims that night.”

Still, the cache of documents offer a new view into the gunman’s mindset through interviews with neighbors, acquaintances and employees of the Las Vegas casinos he frequented.

Those interviewed by the FBI described Paddock as a “strange” introvert who never made eye contact and only wanted to talk about gambling, while the gunman’s fellow gambler told the FBI that Paddock was “very upset” that the red-carpet treatment for high rollers seemed to be fading.

According to the gambler, casinos had previously treated high rollers like Paddock to free cruises, flights, penthouse suites, rides in “nice cars” and wine country tours. But in the years before the Oct. 1, 2017, mass shooting in Las Vegas, the gambler said casinos had begun banning some high rollers “for playing well and winning large quantities of money.” Paddock himself had been banned from three Reno casinos, according to the documents.

Kelly McMahill, a former Las Vegas Metropolitan Police Department official who headed the agency’s criminal investigation into the shooting, said there was no strong indication that Paddock’s actions were driven by resentment toward the casino industry.

“There’s no way that LVMPD would have hidden any potential motive from our victims and survivors for five years,” McMahill said.

10-Minute Barrage Killed 60 People

The 10-minute massacre unfolded on the final night of the three-day Route 91 Harvest Music Festival across the street from the Mandalay Bay resort, where Paddock was staying on the 32nd floor.

Authorities have said Paddock unleashed a barrage of bullets into the crowd of 22,000 people from his corner suite with a commanding view of the Strip and the concert grounds.

His gambling habits made him a sought-after casino patron. Mandalay Bay employees gave him the $590-per-night suite for free and let him use a private service elevator to take up his multiple suitcases. Hidden inside those suitcases were the guns he’d use for the massacre.

A dozen of Paddock’s weapons were modified with rapid-fire “bump stocks,” attachments that effectively convert semi-automatic rifles into fully automated weapons. Some had bipod braces and scopes. Authorities said his guns had been legally purchased.

But before setting up his perch in the Mandalay Bay, Paddock also researched other large venues. He booked rooms overlooking Chicago’s Lollapalooza festival in August 2017 and the Life is Beautiful festival in downtown Las Vegas near the Strip.

“What we know from (Paddock’s internet) search history is that he was looking for a large crowd of people, which, of course, he ended up finding,” said McMahill, the former Las Vegas police official.

A spokesperson for the FBI in Las Vegas declined to comment. In the agency’s final report released in 2019, it said Paddock had sought notoriety in the attack and maybe wanted to follow in his father’s criminal footsteps. The report also said his physical and mental health was declining as his wealth diminished.

Paddock acted alone, killed himself as SWAT officers closed in and left no note about his motive for the rampage.

“If we ever discover a motive, whether it’s 10 years from now, 20 years from now, I have faith that LVMPD would contact victims first before making something public,” McMahill said. “It’s the right thing to do.”