LAS VEGAS — In nearly 30 years with the Las Vegas police, Joseph Lombardo has helped defuse an armed standoff between federal agents and local ranchers, struggled to contain a spike in homicides and defended his officers against accusations of using excessive force against a professional football player.
But nothing could have fully prepared him for last week.
Since a gunman smashed out windows in a casino hotel suite on Oct. 1 and rained bullets on a country music festival, killing 58 people and wounding hundreds more, Sheriff Lombardo has found himself in charge of one of the most frustrating criminal investigations in memory: a mass shooting by a man who seems to have left no public accounting for his actions.
So far, Sheriff Lombardo, a plain-spoken man whose persona contrasts sharply with his city of flashing billboards and jangling slot machines, has not been able to uncover a motive for the shooting. And he has wondered aloud whether something — anything — might have prevented the bloodshed.
“We are always preaching, ‘If you see something, say something,’ ” Sheriff Lombardo told The New York Times last week, in one of his first interviews since the shooting. “So how did we miss this, in the see-something-say-something era? Was there housekeeping personnel that hadn’t received training? Maybe it was a new person? I don’t know the answers to those questions yet.”
Sheriff Lombardo and his subordinates have kept a relatively low news media profile in the aftermath of the shooting. Police leaders here have declined almost all interview requests, have skipped the cable-news circuit and have emphasized that they would speak with a single voice to ensure that only accurate information was released. Las Vegas officials say that that approach limits distractions and allows investigators to get on with their work. But it is a departure from the way major events have been handled by local authorities in other cities, where live broadcast interviews and news leaks have been more common.
Most of what the media gets from Sheriff Lombardo comes at his frequent news briefings, where his answers may be somber, combative or collegial, depending on the question. His relatively tight-lipped approach has drawn attention to his crisis management style.
“He is very methodical,” said Jonathan Thompson, the executive director of the National Sheriffs’ Association, who called Sheriff Lombardo “a lawman’s lawman.” “He is exhibiting years of training to make certain the chain of custody on the evidence is protected, but more important, the rights and safety of his community are protected, too.”
Longtime colleagues say he is a smart tactician with a down-to-earth manner who does not like to speak in public. His handling of the mass shooting and his tight grip on the release of information has drawn praise from Nevada politicians. But the sheriff has also frustrated some people with his reluctance to divulge details about the case, and he has not hesitated to call out journalists for inquiries that he deems superfluous or repetitive.
“That’s just a different way to ask the same question,” Sheriff Lombardo said disapprovingly on Wednesday night when a reporter pressed him about the gunman’s financial records. “I can’t answer that.”
Even as he has warned against speculation and conjecture concerning the case, Sheriff Lombardo has at times shared his own theories about the actions of the gunman, Stephen Paddock.
“Do you think this was all accomplished on his own?” Sheriff Lombardo said in that same briefing on Wednesday. “Face value, you’ve got to make the assumption that he had to have some help at some point, and we want to ensure that that’s the answer. Maybe he’s a super guy, a superhero — not a hero. Super, I won’t use the word. Maybe he’s a super yahoo that was working out all this on his own. But it would be hard for me to believe that.”
As the elected sheriff of Clark County, Sheriff Lombardo has an unusual role for an urban police leader. Unlike most big-city police commissioners, he manages a combined sheriff’s and police department, and is directly accountable to voters. His agency employs about 3,500 police and corrections officers, and patrols a land area larger than Connecticut, much of it unsettled desert.
Elected by a narrow margin to a four-year term, Sheriff Lombardo, a Republican, is in the early stages of a re-election campaign. His political allies say he is a caring man with a sharp memory and analytical mind, but is not a natural campaigner. Steve Wolfson, the Clark County district attorney, said Sheriff Lombardo “was a little rough around the edges” the first time around.
“I said, ‘Joe, smile more — you’re a good-looking guy. You never smile!’ ” said Mr. Wolfson, adding that he had been a friend of the sheriff for about 20 years.
Gary Schofield, who retired from the Las Vegas police this year as a deputy chief, said, “Joe is not a politician,” but rather “a cop who happens to be in a political job.”
Sheriff Lombardo calls himself a moderate and says that, unlike many in his party’s right wing, he supports some forms of gun control.
In the interview with The Times, he said that watching other cities cope with mass shootings had helped shape his own response.
“You have to give authority to boots on the ground to act, without having to ask for permission,” he said.
Aside from leading the investigation into the gunman, he said his most important task after the shooting was to calm the public.
“If we let that information highway get in front of us, it’s hard to come back from chaos,” he said. “So I think it’s important to be clear with what information we do have, and what we do not have.”
On Sunday, the authorities began reuniting concertgoers with the cellphones, lawn chairs and other personal items they had left behind when fleeing the shooting.
Sheriff Lombardo, who worked his way up the ranks of the Las Vegas police before running for sheriff, took over a department that had been scrutinized in 2012 by the Justice Department for frequent police shootings, but was held up as a model for what it did in response, putting changes into place that federal officials had recommended. The federal report noted that black people who were shot by the police were more likely to be unarmed than other people.
“It seems relationships are getting better, and I’ve seen a difference,” said Yvette Williams, caucus chair of the Clark County Black Caucus. “Is there still a lot that needs to be done? Absolutely. But are we on our way? Yes.”
During Sheriff Lombardo’s tenure, homicide rates have risen in Las Vegas, as they have in many other cities, and there has been another increase in shootings involving police officers. Over the summer, an N.F.L. player, Michael Bennett of the Seattle Seahawks, said Las Vegas police had stopped him because he was African-American and had used excessive force while detaining him.
“Las Vegas police officers singled me out and pointed their guns at me for doing nothing more than simply being a black man in the wrong place at the wrong time,” Mr. Bennett wrote at the time.
The accusations attracted national news media attention. Sheriff Lombardo defended his officers, saying they had acted properly.
“He’s had a lot thrown on his plate,” said Steve Grammas, president of the Las Vegas Police Protective Association, the union that represents rank-and-file officers. He added that the sheriff has “had to pivot in 50 different directions.”
William H. Sousa, a criminal justice professor at the University of Nevada, Las Vegas, said that Sheriff Lombardo was part of a generation of reform-minded police chiefs and sheriffs who want to improve community relations and raise training standards.
“I think of him as a progressive chief,” Mr. Sousa said. “He has made a greater effort at transparency, instead of the old ‘this is police business,’ and preventing access to everyone.”
When Sheriff Lombardo’s news conferences were broadcast nationally last week, people who know him personally said they recognized the bluntness and the passion of the lawman in front of the cameras, even if the grimness of the mass shooting had obscured his usually cheerful personality.
“The man that you see at that podium delivering those hard messages to the community is the outstanding leadership individual that I know,” said Jodi Manzella, the executive director of an after-school program where the sheriff serves on the board of directors.
Still, the toll recent events have taken on the sheriff has been obvious. The mayor of Las Vegas, Carolyn G. Goodman, said that “you could see, at each press conference, a growing strain on the physical body.”
“It’s hard — this is not an easy thing to be doing,” Ms. Goodman said. “And I look in his face, and I can see — as well as he’s doing with everything, which is great — I can see the stress and the strain.”
An earlier version of this article misstated the surname of the caucus chair of the Clark County Black Caucus. She is Yvette Williams, not Thompson.