LAS VEGAS — FBI agents questioned the Las Vegas gunman's girlfriend on Wednesday as they struggled to get inside the mind of Stephen Paddock, a frustratingly opaque figure who carried out his high-rise massacre without leaving the plain-sight clues often found after major acts of bloodshed.
Three days after Paddock gunned down 59 people, Marilou Danley was interviewed at the FBI's office in Los Angeles and had an attorney with her, according to a law enforcement official who was not authorized to discuss the case publicly and spoke on condition of anonymity.
Danley, 62, who has been called a "person of interest" by investigators, was met by federal agents Tuesday night when she arrived at the Los Angeles airport from her native Philippines after more than two weeks abroad.
Investigators are busy reconstructing Paddock's life, behavior and the people he encountered in the weeks leading up to the deadliest mass shooting in modern U.S. history, FBI Deputy Director Andrew McCabe said. That includes examining his computer and cellphone.
But as of Wednesday, investigators were unable to explain what led Paddock to rain heavy fire down on a country music festival Sunday night from the windows of his 32nd-floor room at the Mandalay Bay hotel casino. He killed himself as police closed in. The attack left more than 500 people injured.
"This individual and this attack didn't leave the sort of immediately accessible thumbprints that you find on some mass casualty attacks," McCabe said.
The 64-year-old retired accountant quietly stockpiled an arsenal of high-powered weapons while pursuing a passion for high-stakes gambling at Nevada casinos, where his game of choice was video poker, a relatively solitary pursuit with no dealer and no humans to play against.
Neighbors described Paddock as friendly, but he wasn't close to them.
"He was a private guy. That's why you can't find out anything about him," his brother, Eric Paddock, said from his home in Florida. As for what triggered the massacre, the brother said: "Something happened that drove him into the pit of hell."
Occasionally, Paddock shared news of his gambling winnings, his brother said, recalling a photo text message he received showing a $40,000 payout.
It was in a casino where Paddock met his girlfriend, who was a high-limit hostess for Club Paradise at the Atlantis Casino Resort Spa in Reno, Eric Paddock told The Washington Post.
Danley's sisters in Australia said that they believe she was unaware of Paddock's murderous plans and that he sent her away so she wouldn't interfere.
In a TV interview in Australia, the sisters — whose faces were obscured and their names withheld — called Danley "a good person" who would have stopped Paddock had she been there.
"She didn't even know that she was going to the Philippines until Steve said, 'Marilou, I found you a cheap ticket to the Philippines,'" said one of the sisters, who live near Brisbane.
A brother, Reynaldo Bustos, told ABC from his home outside Manila that Danley had assured him: "Do not panic. I have a clean conscience."
A receptionist at the office of Los Angeles-based defense attorney Matthew Lombard confirmed he was representing Danley but would not comment further.
Paddock wired $100,000 to the Philippines days before the shooting, a U.S. official not authorized to speak publicly because of the continuing investigation said on condition of anonymity. Investigators are trying to trace that money.
Also, casino regulators are looking closely at Paddock's gambling habits and checking their records to see whether he had any disputes with casinos or fellow patrons. In addition, investigators are examining a dozen financial reports filed in recent weeks when he bought more than $10,000 in casino chips.
Paddock had no known criminal history. Public records contained no indication of any financial problems, and his brother described him as a wealthy real estate investor.
"I believe, based on what I have been told, the issue was not that he was under financial stress," said Sen. Claire McCaskill of Missouri, the ranking Democrat on the Homeland Security Committee.
President Donald Trump and first lady Melania Trump met privately with victims at a Las Vegas hospital Wednesday and then with police officers and dispatchers, praising them and the doctors who treated the wounded.
He didn't address those grieving until the end of his visit, when he called it a "very sad day for me personally."
"Our souls are stricken with grief for every American who lost a husband or a wife, a mother or a father, a son or a daughter," he said. "We know that your sorrow feels endless. We stand together to help you carry your pain."
Paddock had stockpiled 47 guns since 1982 and bought 33 of them, mostly rifles, over the past year alone, right up until three days before the attack, Jill Snyder, an agent with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, told CBS on Wednesday.