LAS VEGAS — Authorities in Las Vegas said Tuesday that the gunman who killed at least 58 people at a country music festival ‘‘extensively’’ planned the massacre, placing cameras in his room and the nearby hallway so he could see when police officers were closing in.
‘‘It was preplanned, extensively, and I'm pretty sure that he evaluated everything that he did in his actions, which is troublesome,’’ Joseph Lombardo, the sheriff of the Las Vegas Metropolitan Police Department, said at a briefing Tuesday afternoon.
Lombardo said one of the cameras was hidden in a food service cart in the hallway outside the suite. Law enforcement officials said the purpose of that camera was apparently to give the gunman, Stephen Paddock, a video feed that would warn him when police were closing in.
People close to the investigation also disclosed that in the weeks before the attack, Paddock transferred a large amount of money — something close to $100,000 — to someone in the Philippines, possibly his girlfriend.
In his hotel room, investigators also found 12 ‘‘bump stock’’ devices that can enable a rifle to fire continuously, like an automatic weapon, authorities said.
Officials said Paddock had been stockpiling guns since 1982 and bought 33 firearms in the last year.
Investigators have sifted through a chilling but baffling array of clues in the wake of the deadliest mass shooting in modern American history, trying to determine the chain of events that caused a 64-year-old to gun down concertgoers from his hotel suite overlooking the Las Vegas Strip. No clear motive has emerged.
‘‘I can’t get into the mind of a psychopath,’’ Lombardo had said Monday.
The probe into the shooting stretched from a ranch-style home near the Arizona border to the 32nd-floor hotel suite used by Paddock as a place to scan the crowds at the festival and then open fire — leaving hundreds injured in the rain of bullets or trampled in the panicked rush for cover late Sunday. He then killed himself as SWAT officers closed in.
Once again, a stunned nation was left to grapple with a city riven by tragedy and a resurgent debate over gun control and gun violence. The White House and many Republicans said it was a time to mourn rather than launch into political battles, while some Democrats renewed calls for gun safety legislation.
Lombardo warned that the number of dead in Las Vegas could rise. Hospitals across the region continued to treat patients from the scene, many of them seriously injured. Sunrise Hospital and Medical Center said that it had 68 patients from the rampage, 33 of them in critical condition.
Authorities described a grim amount of preparation by the shooter. Police said Paddock arrived on Thursday, three days before the shooting, at the Mandalay Bay Resort and Casino on the southern end of the Las Vegas Strip. He took more than 10 suitcases into his suite, officials said.
Paddock aroused no suspicion from hotel staff even as he brought in 23 guns, some of them with scopes. One of the weapons he apparently used in the attack was an AK-47-type rifle, with a stand used to steady it for firing, people familiar with the case said.
Paddock kept the “Do Not Disturb” sign on his door for the next three days, so no maids entered the rooms, a housekeeping manager told The New York Times.
When police breached his hotel room door and stormed inside, they found him already dead, with blood spread out behind him, mixed in with the empty shell casings on the carpet.
Officials recovered another 19 guns as well as thousands of rounds of ammunition and the chemical tannerite, an explosive, at Paddock’s home in Mesquite, Nev., and seven at his Reno house. They also found ammonium nitrate, a chemical that can be used in bomb-making, in Paddock’s vehicle, Lombardo said.
Lombardo also said the department has opened an investigation into the unauthorized release of images that show the crime scene, including the bullet-riddled door to the suite used by Paddock. Police said Paddock fired at hotel security before taking his own life.
In the photos, obtained by the German newsmagazine Bild on Tuesday, a portion of Paddock’s two-room suite is visible. A gun with a scope and a stand can also be seen inside the room, just behind yellow crime-scene tape.
Paddock had purchased weapons legally over a period of years, from local stores near his homes and from major retailers, like Cabela's, according to law enforcement officials.
Police said they believe Paddock was a ‘‘lone wolf’’ attacker.
Marilou Danley, Paddock’s 62-year-old girlfriend, was found outside the country — as of Monday afternoon, in Tokyo — and was not involved in the shooting. Danley is expected to return from the Philippines for questioning, a federal law enforcement official told The New York Times.
‘‘We still consider her a person of interest,’’ Lombardo said Monday. He said investigators also are exploring a report that Paddock attended a different music festival in September.
When he spoke to the FBI, Eric Paddock, the shooter’s brother, said he showed agents three years of text messages from his brother, including one that mentioned winning $250,000 at a casino. A federal law enforcement official said investigators had reviewed reports suggesting Paddock engaged in high-dollar gambling, and they are trying to determine whether he faced financial strains.
The rampage Sunday targeted the Route 91 Harvest festival, a three-day country music concert with grounds across the street from the Mandalay Bay Resort. When the gunfire began Sunday at about 10:08 p.m., some 22,000 people were there, according to police.
The dead included a behavioral therapist who was soon to be married, a nursing assistant from Southern California, a commercial fisherman, and an off-duty Las Vegas city police officer. Two other officers who were on duty were injured, police said; one was in stable condition after surgery, and the other sustained minor injuries. Another off-duty officer with the Bakersfield Police Department in Southern California also sustained non-life-threatening injuries.
Syed Saquib, a surgeon on duty Sunday night at University Medical Center, said the hospital treated 104 patients, most of whom had gunshot wounds.
President Trump ordered flags flown at half-staff and said he would visit Las Vegas on Wednesday.
Trump repeated his praise for police in Las Vegas and their response, saying of law enforcement that ‘‘what happened in Las Vegas is in many ways a miracle.’’ He also said that ‘‘we'll be talking about gun laws as time goes by.’’
In 2013, Senator Dianne Feinstein of California proposed outlawing bump stocks, but Congress has not acted on her proposal. She proposed a ban again on Tuesday.
Senator Mitch McConnell, Republican of Kentucky and majority leader, rebuffed questions about potential legislative action Tuesday, saying that the massacre was being politicized.
“Look, the investigation’s not even been completed,” McConnell said. “And I think’s it’s premature to be discussing legislative solutions, if there are any.”