Stephen Paddock appeared to be settling into a quiet life a few years ago when the 64-year-old apartment manager and avid gambler bought a home in a quiet Nevada retirement community about an hour's drive from the Las Vegas Strip and his beloved casinos.
Those who knew Paddock say there was no sign he was capable of holing up in a room on the 32nd floor of a casino hotel, the Mandalay Bay, and opening fire with multiple guns on a country music festival, killing at least 59 people and wounding more than 520 in the worst mass shooting in modern US history.
"He was a wealthy guy and he liked to play video poker and he liked to go on cruises," the gunman's seemingly baffled brother Eric Paddock told reporters from his doorstep in Orlando, Florida, on Monday.
"He's never drawn his gun, it makes no sense," Eric Paddock said.
He said he was aware that his brother had a couple of handguns he kept in a safe, perhaps a long rifle, but no automatic weapons.
Police say they recovered a total of 34 weapons belonging to Paddock, including 16 from the hotel room and 18 at his home in Mesquite, a small desert town popular with golfers and gamblers. Some were automatic weapons or semi-automatic rifles illegally modified into machine guns.
Eric Paddock described his brother as peaceful, saying he moved back to the red desert hills of Nevada because gambling is legal there and he hated Central Florida's humidity.
Paddock apparently lived in Mesquite with his girlfriend, who was in Tokyo at the time of the shooting. Las Vegas police said they were seeking to interview her when she returned. Authorities said she had no connection with the attack.
The brothers were last in touch in early September, exchanging text messages about power outages after Hurricane Irma slammed into Florida, where their mother still lives.
"He had nothing to do with any political organisation and religious organisations", Eric Paddock said.
ITINERANT EXISTENCE, GAMBLING
Their father was Patrick Benjamin Paddock, a bank robber who was on the Federal Bureau of Investigation's Most Wanted list in the 1960s and essentially unknown to his sons. The shooter himself had no criminal record, Las Vegas police said.
In recent weeks, Paddock made gambling transactions worth tens of thousands of dollars, although it was unclear whether they were wins or losses, NBC News reported, citing unidentified law enforcement officials.
Public records point to an itinerant existence across the American West and Southeast: Florida, a few years in California, a few years in other parts of Nevada.
A spokeswoman for Lockheed Martin said Paddock worked for a predecessor of the company from 1985 to 1988, but offered no other details.
Paddock had a hunting license in Texas, where he lived for a while. He got his pilot license and had at least one single-engine aircraft registered in his name.
In early 2015, he bought a modest two-story home in a new housing development for retirees on the dusty edge of Mesquite, which straddles Nevada's border with Arizona.
"It's a nice, clean home and nothing out of the ordinary," Quinn Averett, a Mesquite police department spokesman, told reporters on Monday.
The FBI said Paddock had no connection with international militant groups.
Before moving to Mesquite, Nevada, he lived in another town called Mesquite, in Texas, where he worked as the manager of an apartment complex called Central Park.
The Washington Post reported that Paddock had also worked as an accountant and had real estate investments.
Records as recent as 2015 list Paddock as single, though it appears he may have married while living in California in the 1980s.
Paddock's age places him in the minority of mass shooters, said Laura Dugan, professor of criminology at the University of Maryland."Most shooters are fairly young," Dugan said.
"Right now with this particular case, it's baffling. Why would a guy in his 60s who seems to be well off go and do a thing like that?"