Sheriff Joseph Lombardo described Paddock as a narcissist and "status-driven" and said his financial decline "may have a determining effect on why he decided to do what he did."
Lombardo's statements, made during a wide-ranging interview with CNN affiliate KLAS
, are the closest a law enforcement official has come to articulating a possible motive in the October 1 attack in which at least 58 people were killed and more than 500 were wounded.
But Lombardo said later in the interview that he did not know whether money troubles led to the shooting. He reiterated that the motive remains elusive.
"What is the reason why?" he asked rhetorically at one point. "We haven't gotten that answer yet."
"There was something that popped his trigger or caused him to go into that direction and we have yet to determine what that is," Lombardo added. "I hope we find something in the pathology of his brain that helps us understand this."
The Las Vegas Metropolitan Police Department did not respond to CNN for comment on issues discussed in Lombardo's interview with KLAS' George Knapp.
In the interview with Knapp, the sheriff characterized Paddock as a "lone actor" who struggled with bouts of depression. He said investigators had not discovered any links to extremist groups and that the only political statement he was known to have made was that "he was happy with Trump because the stock market was doing well."
The sheriff spoke for more than an hour in the interview marking one month since the attack. The sheriff spoke openly about the planning, execution and aftermath of the shooting and search for a motive, at times speculating about aspects of the case.
Asked about the periodic gaps in Paddock's firing as he unleashed a barrage of more than 1,000 rounds on concertgoers across the street from the Mandalay Bay hotel, Lombardo speculated that he was assessing the crowd, changing ammunition and looking at monitors that gave him a view into the hallway outside his room.
"Who knows what's going through his psychotic mind," the sheriff said.
Lombardo brushed aside questions about changes to the timeline regarding how precisely the attack unfolded and when police first arrived on the scene. He called his officers' response time "pretty amazing."
He said Paddock still had access to more than 4,000 rounds of ammunition and "had the ability to do a lot more harm."
Lombardo is convinced, he said, that Paddock took his own life because he was aware of the police presence outside his room and the sheriff said that by being there, his officers saved lives.
"I honestly believe that he believed the wolf was at the door," Lombardo said.
The sheriff said investigators are continuing to interview Paddock's girlfriend, Marilou Danley, who has told authorities she had no inkling Paddock was plotting a massacre.
Knapp asked Lombardo if he believed her account.
"In general, from what I'm being told from investigators, that assessment is accurate," he said.
"But personally, it's hard for me to believe," the sheriff added, noting that Paddock had acquired dozens of weapons.
"You would think that Miss Danley would have some information associated to that," he said. "But currently we haven't been able to pull that out of her -- if it's in her."
Efforts to reach Danley's attorney were not immediately successful.
The top FBI agent in Las Vegas also spoke with a local reporter around the time of the one-month mark but offered considerably less detail than Lombardo.
"I feel like we are going in the correct direction to understand why this happened," Aaron Rouse, the special agent in charge of the FBI's Las Vegas field office, told the Las Vegas Sun.
Rouse asked for the public's patience as agents work toward that conclusion. "It won't be as fast as people would want it to be," he told the paper.
The FBI declined to make Rouse available for an interview with CNN.