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The girlfriend of the Las Vegas gunman, Marilou Danley, is at the F.B.I.’s building in Los Angeles for questioning, according to a law enforcement official.
Ms. Danley, 62, who had been overseas since before the shooting but returned to the United States on Tuesday night, is one of the few people who might know what drove the gunman, Stephen Paddock, to kill 58 people and wound hundreds more from a Las Vegas hotel this week.
She is considered a “person of interest” in the investigation of the attack, Sheriff Joseph Lombardo of the Las Vegas Metropolitan Police Department said Tuesday afternoon.
It is not clear what, if anything, Ms. Danley knew about Mr. Paddock’s methodical plans to stockpile weapons and ferry them into a 32nd-floor hotel suite to commit mass murder. She had been in the Philippines from Sept. 25, roughly a week before the shooting, until Tuesday, when she flew from Manila to Los Angeles, according to Antonette Mangrobang, a spokeswoman for the Philippine Immigration Bureau.
Mr. Paddock had recently wired thousands of dollars to the Philippines, a law enforcement official said.
“Person of interest” is a vague term that does not necessarily indicate that the person is suspected of committing a crime. Ms. Danley has not been charged with any crime.
Federal agents met Ms. Danley at her plane at Los Angeles International Airport, according to a law enforcement official. The official, who spoke on condition of anonymity because she was not authorized to speak to the news media, said Ms. Danley was not under arrest.
Television crews waited for Ms. Danley to emerge from customs at the international terminal. Hours after her flight landed, an airport police officer said she had been led out through a side exit after going through customs. NBC News posted a brief video that it said showed Ms. Danley in a wheelchair, being escorted by security officers.
In an interview with an Australian news station, two sisters of Ms. Danley said she had been sent to the Philippines two weeks before the shooting.
“He sent her away so that he can plan what he is planning without interruptions,” one sister said. “In that sense, I thank him for sparing my sister’s life.”
But she said that would not compensate for the dozens who were killed.
The two sisters were interviewed anonymously, with their faces obscured. Ms. Danley’s sisters Liza Werner and Amelia Manango live in Australia.
“She didn’t even know she was going to the Philippines until Steve said, ‘Marilou I found you a cheap ticket to the Philippines,’” one of the sisters said.
They said their sister was “madly in love” with Mr. Paddock and that she “probably was even more shocked than us” by the shooting. And they vouched for their sister’s character, calling her a “gentle soul.”
“He done this solely himself,” one said.
Family members and former neighbors were shocked to see Ms. Danley’s name surface in connection with the shooting on news reports, as the police sought to find her hours after Mr. Paddock killed himself in his hotel room.
“She’s probably one of the most happy, outgoing, full-of-life people I’ve ever known,” said Dionne Waltrip, Ms. Danley’s former stepdaughter, who lives outside Fayetteville, Ark. “Everyone who has ever met her likes her.”
Ms. Waltrip said her father, Geary Danley, traveled the world as an auditor for FedEx and met his future wife overseas.
Ms. Danley has ties to the Philippines, and several news reports said she was born there. She spent many years in Australia, where news reports said she was married, and is an Australian citizen.
After meeting Mr. Danley, she moved to Memphis. The couple wed in 1990 and their marriage lasted 25 years.
Ms. Danley worked retail jobs, selling mostly clothing and jewelry. Both she and Mr. Danley had children from prior relationships. Ms. Waltrip was 20 when the couple got together; Ms. Danley has a daughter who now lives in California. The couple moved to Nevada when they retired.
“They were extremely happy,” Ms. Waltrip said. “They loved each other very much.”
But before the marriage ended, Ms. Danley met Mr. Paddock. She was working at a casino and he was a high-limit player, casino employees said. She worked there from 2010 to 2013, according to her LinkedIn account.
John Weinreich, an executive casino host at the Atlantis Casino Resort Spa at the time, said he believed that Ms. Danley frequently attended to Mr. Paddock, serving him food and pointing out which machines might be ripe for a payout, and eventually became his regular host.
“Then she was just gone one day,” he said. “I asked some fellow workers and they said she went off with Stephen.”
She and Mr. Danley divorced in 2015. On the divorce papers, she listed her address as a condominium in Reno owned by Mr. Paddock.
At the hilltop subdivision where the Danleys lived in Sparks, Nev., before the divorce, neighbors described Ms. Danley as a chatty extrovert who hosted cookouts and brought copious amounts of Filipino food to the semiannual block parties.
“She was always cooking,” said Christine Riley, 46, a dietitian who lived a few doors down from Ms. Danley’s former residence.
But when Ms. Danley was living with Mr. Paddock in a Reno subdivision, the couple were not viewed as sociable. “I thought maybe he was sick or something, because they were always in the house and the shades were always drawn shut,” said Susan Page, a retired financial analyst who was the couple’s next-door neighbor.
Ms. Page said she occasionally saw Mr. Paddock working on an older sport utility vehicle that seemed to be Ms. Danley’s car, and other neighbors said he had a large safe in the garage.
“They weren’t outgoing,” she said. “They didn’t participate in anything. Everybody around here, they go over to each other’s houses, they have a drink and they chitchat.”
Ms. Page added, “It wasn’t that they were unfriendly, they just didn’t socialize.”
On her own, Ms. Danley could be friendly. Connie Allred, a 68-year-old retired dental receptionist, occasionally attended Zumba classes with Ms. Danley at the subdivision’s clubhouse. She described Ms. Danley as a warm “world traveler” who went abroad several times a year and visited family in the Philippines and Los Angeles.
“She was always gone,” Ms. Allred said. “She’s a hard one to keep track of. We’d be in Zumba and then all of a sudden she would say, ‘I’m leaving for a couple months,’ and then she’d be back and then she’s traveling other places.”
Philippine immigration officials said Ms. Danley left Manila on Sept. 22 for a trip to Hong Kong and returned on Sept. 25.
Eric Paddock, Mr. Paddock’s youngest brother, said his brother loved Ms. Danley and doted on her. For her part, he said, Ms. Danley made compromises like doing without perfume, hair spray and bubble baths in order to not set off his allergies. Though his brother was a multimillionaire, he said, he did not believe she was with him because he had money.
Some people who knew Mr. Paddock said he could take on an imperious, exacting demeanor. But with Ms. Danley, he was different, Eric Paddock said.
“She was probably one of the only people I’ve ever seen that he’d go out of his way to do a little thing for,” he said. “He went out of his way to be nice to her. This is not something Steve does — go out of his way.”
He added: “Steve expected people to wait on him for the most part. But he waited on her sometimes. He would do what she wanted to do. He would defer to her in the way that he wouldn’t to the rest of humanity. Even me.”
Reporting was contributed by Adam Baidawi, Adam Goldman, Miriam Jordan, Serge F. Kovaleski, Bret Schulte, Megan Specia, Sabrina Tavernise and Felipe Villamor. Susan C. Beachy contributed research.