The victim toll rose to 58 dead and 527 injured

The shooter who rained deadly gunfire from a high-rise Las Vegas hotel onto a concert crowd below him on Sunday night had 47 firearms that were recovered by police in three separate locations, as well as a very large amount of ammunition, according to police.

The locations were inside the hotel room from which the suspect shot at hundreds of people, as well as Verdi and Mesquite, Nevada. The firearms were purchased across four states: Nevada, Utah, California and Texas.

On Monday, police said 23 guns were found in the shooter’s hotel suite, another 19 at his home, and several pounds of material used to make explosives in his car.

Even as the number of victims climbed yet again — the revised toll now is 58 dead and 527 injured, in the nation’s deadliest single-gunman mass shooting in modern times — authorities still say they have no sign of a motive that might have driven 64-year-old Stephen Paddock to act before he shot himself as SWAT officers moved in on him.

Authorities said Monday night that a motive for the homicide investigation was still unclear, but that police were “hunting down and tracing down every single clue we can get on his background.”

MGM Resorts was coordinating rooms for families of victims who were traveling into Las Vegas, and they were also coordinating travel through Southwest Airlines.

While countless people lined the streets willing to donate blood, authorities said they had “enough blood donations to last into the foreseeable future.”

“I can’t get into the mind of a psychopath at this point,” Clark County Sheriff Joseph Lombardo said at an earlier news conference Monday

The city’s mayor, Carolyn Goodman, told the media: “October 1, 2017, will be one of the darkest days ever.”

Authorities also confirmed they want to further interview a woman they’ve tentatively identified as Paddock’s girlfriend, Marilou Danley, who was located out of the country after the attack. “I believe she is in Tokyo,” Lombardo said.

The investigation is proceeding at four sites, from the 32nd-floor suite in the Mandalay Bay Resort hotel that served as Paddock’s sniper’s perch, to the nearby outdoor concert field that held some 22,000 people when the gunshots rang out, to the shooter’s retirement community home in nearby Mesquite, and finally to another residence belonging to Paddock in Reno, where a SWAT team stood by cautiously on Monday before entering, because “we want to make sure there is no booby traps,” the sheriff said.

He said authorities have learned that Paddock may have attended a festival in Las Vegas in September, before settling last Thursday into his hotel room overlooking the Route 91 Harvest music festival. Country artists Jason Aldean was onstage Sunday night as the initial pop-pop-pop of gunfire sent festival-goers scrambling.

Among the guns discovered in Paddock’s possession were those that Lombardo characterized as assault weapons, some of which Lombardo said investigators believe were modified after their original purchase to be fully automatic. The shooter used multiple rifles during his attack, and some of those rifles were equipped with a scope, he said.

Explosives and several thousand rounds of ammunition were recovered at Paddock’s Mesquite home, along with several pounds of Tannerite, an explosive powder available at any gun store, the sheriff said.

One Mesquite gun shop, Guns & Guitars, has identified Paddock as a customer, saying in a statement obtained by PEOPLE that Paddock passed all necessary background checks “required by local, state and federal law” and “never gave any indication or reason to believe he was unstable or unfit at any time.”

Authorities have identified at least one other gun dealer, in Arizona, from whom Paddock obtained weapons, according to the sheriff.

Asked if gambling debt may have led the real-estate investor and former accountant identified by his brother as a “high-stakes” gambler, Lombardo said, “We haven’t had the opportunity to evaluate that.”

Police and the hotel’s security staff were able to zero in on Paddock’s location in the hotel by moving floor-to-floor before they approached the large two-room suite from which it appeared the shots were coming. From inside the room, shots then were fired through the doorway and injured a security guard in the leg, Lombardo said.

The officers then backed off before SWAT officers responded.

“As of right now, all the confirmed fatalities have been recovered,” John Fudenberg, the Clark County coroner, told the news conference. He added, however, “that number, unfortunately, may go up.”

• With reporting by DIANE HERBST