Marilou Danley, the longtime girlfriend of the Las Vegas gunman, returned to the United States on and was met at the Los Angeles airport by FBI agents.
Authorities are hoping she can shed light on what drove Stephen Paddock to open fire from his casino hotel room. He killed at least 58 people and injured more than 500 on the Las Vegas Strip before killing himself.
Danley was in the Philippines at the time of the attack. Immigration officials in the Philippines told news outlets there that Danley left the country Tuesday evening on a Philippine Airlines flight to Los Angeles.
As investigators continue to search for a motive, new details have emerged about Paddock and his relationship to Danley.
Paddock met Marilou Danley several years ago while she was working as a high-limit hostess for Club Paradise at the Atlantis Casino Resort Spa in Reno, Nevada, said his brother Eric Paddock.
"They were adorable - big man, tiny woman. He loved her. He doted on her," Eric said.
The two often gambled side by side, he said. Authorities say that prior to the shooting Paddock transferred a large amount of money - close to $100,000 - to someone in the Philippines, possibly his girlfriend. Eric Paddock said he now believes his brother may have been trying to arrange for Danley to be abroad before carrying out his massacre.
Employees at a Starbucks in Mesquite, Nevada, however, described the couple's relationship differently. A supervisor at the coffee shop told the Los Angeles Times that Paddock often berated Danley in public. The Starbucks is the only one in town and is inside the Virgin River Casino.
"It happened a lot," Esperanza Mendoza, supervisor of the Starbucks, told the Times. He would verbally abuse her when Danley asked to use his casino card to buy food or other things inside the casino, Mendoza said.
"He would glare down at her and say - with a mean attitude - 'You don't need my casino card for this. I'm paying for your drink, just like I'm paying for you.' Then she would softly say, 'Okay' and step back behind him. He was so rude to her in front of us."
Danley is from the Philippines but has Australian citizenship, Australian authorities have said.
The Courier Mail, a newspaper in Brisbane, the capital of Queensland, Australia, posted pictures of a trip to Australia Paddock apparently took with Danley in 2013 to meet her family there.
Danley arrived in the Philippines a week before the attack, Filipino news outlets said, quoting immigration officers at the Ninoy Aquino International Airport. The officers told local news outlets that she arrived in Manila from Hong Kong on Sept. 25 via Cebu Pacific flight 5J 115.
Paddock was a frequent gambler at the casino where Danley once worked. She was a high-limit hostess for Club Paradise, a rewards program in the Atlantis Casino Resort Spa in Reno, Nevada, according to her LinkedIn profile. In a statement, Atlantis officials said she has not worked for the casino for several years.
Paddock was such a regular at the Atlantis that his entire family once took over the top floor at the casino's expense, his brother said.
According to court records, Danley may have been living with Paddock as early as August 2013, while she was still married to another man, named Geary Danley.
Geary and Marilou Danley were married in Las Vegas in 1990. According to court records, they jointly filed for divorce on Feb. 25, 2015, and the divorce was finalised the next day. During her divorce, Marilou Danley listed a downtown Reno apartment as her address. Property records show the apartment was owned by Paddock.
Paddock invested and sold several properties in recent years as a way of making money, according to relatives and property records. Neighbours at two other properties owned by Paddock in Reno and Mesquite said Danley lived with Paddock there as well and often disappeared with him for long stretches - sometimes for months at a time - during his visits to casinos.
At one point, Danley worked for an airline based out of California's Bay Area, said one longtime neighbour in Reno, where Danley and Paddock lived together in a retirement community. She later worked for Avon, the cosmetic sales company, and tried to sell their products to other residents, Elizabeth Tyee said. Danley traveled all the time, and when she was at the home she shared with Paddock in a retirement community in Reno, it was never for very long. Tyee said Danley would show up every three or four months and stay for no more than 10 days.
She is considered a critical witness in trying to decipher Paddock's motive.
While investigators have described her as a "person of interest," they have not suggested that she is considered an accomplice or involved in any way. Still, given how little has emerged in Paddock's past that could foreshadow the attack, the "best lead is through this girlfriend," said Sen. Dean Heller, R-Nev.
Danley has a daughter and grandchildren, Tyee said. Tyee and many other neighbours described Danley as extremely sweet and friendly. She hugged her when they saw each other. Paddock, however, was more standoffish and unfriendly.
This summer, Tyee saw Danley and Paddock moving a mattress and saw inside their garage, which was completely empty. Tyee asked Danley whether they were moving, and Danley said they had bought a new house but were not moving out of Reno.
Another neighbour, Susan Page, who moved next door to the couple this summer, said she had not seen them since August. Paddock had recently bought a new silver minivan, she said, and Danley drove an SUV. On the third week of August, Paddock left the house. Soon after, Danley packed up her car as well, as if she was moving, Page said.
More details have also emerged on Paddock, the gunman.
From 1976 to 1985, Paddock worked U.S. government jobs: as a letter carrier for the U.S. Postal Service, an agent for the IRS and an auditor for U.S. government's Defense Contract Audit Agency, according to the Office of Personnel Management.
Neighbours in several states where he owned homes in retirement communities described him as surly, unfriendly and standoffish.
Relatives say the roots of Paddock's loner lifestyle may have been planted July 28, 1960. On that day, when Paddock was 7, a neighbour from across the street took him swimming. The neighbour at the time told a local newspaper that she knew authorities were coming for his father, a bank robber, and she wanted to spare the boy the trauma of seeing his father hauled away by authorities.
From that point on, Paddock's family was never the same.
His mother struggled to raise him and his brothers on her own. His father escaped from prison - twice - and had little more contact with them, relatives say. As they grew older, Stephen, the eldest, and the youngest brother, Eric, kept in touch, but Stephen Paddock drifted almost completely out of touch with his two other brothers, Bruce and Patrick.
Eric said that Stephen stopped talking to his brother Bruce because Bruce used to beat him up when they were kids and that Stephen stopped talking to Patrick because they're very different people.
Even with Eric he never talked much. They created a lucrative real estate investment business together, but Stephen would only text Eric now and then.
"We didn't talk much. We talked when there was something to talk about," Eric Paddock said. "Steve had no help. Steve did not take help. He was a stand-alone guy."
Choking up as he talked, Eric said: "Steve was like a dad surrogate. He took me camping. I liked my brother. He was a good guy."
Stephen Paddock went to John H. Francis Polytechnic High School, in the Los Angeles suburbs, his brother said.
Judy Smith Nelson, a retired federal worker living in Las Vegas, was stunned when she first saw that she and the alleged shooter were the same age - 64. Then a friend texted her a picture from an old high school yearbook.
"I couldn't believe it. I recognised the face. We had been classmates," Nelson said.
As investigators continued searching for a motive, anyone who had come into contact with Paddock over more than four decades began to wrestle with what they knew of the man and whether there had ever been clues of what would come.
Former California state senator Richard Alarcon, who had gotten his start as student body president of John H. Francis Polytechnic High School in 1971, posted a note to friends on Facebook on Tuesday saying he remembered playing basketball with Paddock at a neighbourhood court.
Another classmate remembered Paddock showing up at a 20-year reunion and repeatedly angling to talk to her.
Nelson, in Las Vegas, fished through an old box of keepsakes and found a 10-year reunion program that contained a one-line description that each classmate had written. Paddock's read: "Single, accountant, has traveled to Hollywood, lives in Sepulveda [Calif.]"
"We're all just reeling, and here I have kind of a personal connection, being that we walked the same grounds, we were from the same area," Nelson said.
After high school, Paddock attended Cal State Northridge. He was married and divorced twice. Both ex-wives - one in the L.A. area, the other in the Dallas suburbs - declined to talk to reporters.