In America's macabre recent history of mass shootings, it has become something of a cliche: the loner who moved silently in his community, never getting too close to neighbors or revealing his hand.

Stephen Paddock, the gunman behind the deadliest such attack in modern US history who murdered 59 people in Las Vegas on Sunday, joins that chilling roll call of reclusive killers.

Neighbors in Mesquite, a fast-growing casino town on Nevada's border with Arizona, described their shock Tuesday at discovering the evil lurking within their close-knit locale of fewer than 20,000.

"I didn't realize until I started watching the news that the lunatic lived right here. When I heard he lived in Mesquite and I saw all the traffic, that's when it sunk in," said Rod Sweningson, whose home is yards from Paddock's stone-clad and faux stucco bungalow.

Sweningson recalled his alarm when the FBI showed up in the small hours of Monday, letting neighbors know they were about to hear a bang as federal agents broke into the killer's potentially booby-trapped home.

Earlier that night, officers had found 23 firearms -- including 16 assault rifles -- inside Paddock's 32nd floor room at the Mandalay Bay hotel on the Las Vegas Strip, where Paddock had killed himself before they arrived.

"I suspect that from what they found... they had no idea what was going on in that house. I think they took every precaution they could when they went in. They weren’t joking around," Sweningson told AFP.

He described that part of Mesquite as a "quiet, sleepy little community" where security was usually an afterthought.

"We've never even thought about our locking doors. We didn't know we lived two doors down from a lunatic."

He added that, even though he lived among them, neighbors hardly ever clapped eyes on Paddock.

"We could have passed each other going back and forth to the mailbox -- and we probably did a number of times -- but even now, looking at the news, I don't know him," he said.

-'Too close to home' –

Residents speculated that Paddock may have played golf and that he was to be found occasionally having lunch at the local senior citizens' club, although staff at the club itself said they did not have his name on any visitors list and didn't recognize his face, a mainstay on television news in the last 24 hours.

Freelance writer and local resident Teri Nehrenz revealed that she had lived in the next town along from Bath, Ohio, where "Milwaukee Cannibal" Jeffrey Dahmer grew up, and says she even dated someone who went to school with the notorious serial killer.

"That was bad enough, now this is a second time. It kind of has a tendency to rattle a person a little bit," she told AFP, breaking down in tears.

"It's a little too close to home. You always think you're protected from this kind of thing and it slaps you in the face that you are not."

The 54-year-old, who has covered community events in Mesquite for the local newspaper for several years, described Paddock as having gone "completely under the radar" since moving in from Florida two years ago.

"I have spoken with people I know who work at the casinos in the cashier positions.

"He did frequent the casinos -- he was very into gambling -- but he stayed with the machines. He didn't interact with the hotel security guards, never caused any problems with them, never got a traffic ticket in the city," Nehrenz told AFP.

-'Pretty numb' -

"He never attended any community events. Civic organizations -- he didn't belong to any of those. I heard he might have golfed... He's the most notoriously unknown person in town, seriously."

Nehrenz said one of Paddock's neighbors had revealed that he would occasionally embark on "political rants" but she added that the neighbor "didn't specify what party or whether he was angry-political or whatever."

Nehrenz described the community of fewer than 20,000 residents as "pretty numb."

"It was shocking, and more than a little devastating, but we have a strong community here -- one of the best -- they'll pull together through it.

"They are handling it. It was a very quiet day here yesterday. We had friends and family members here in Mesquite who were attending the concert, of course. A couple were injured but okay. One returned, thank God, uninjured."

Mesquite, one of the fastest-growing towns in the US, is a traditional stopping point on the road from Las Vegas to Salt Lake City.

The community around Paddock's home is described by residents as mainly elderly, with affluent inhabitants who often spend their summers in cooler nearby ski resorts such as Park City, Utah.

"If people don't come knocking on your door -- the people here respect the quiet that most people come to get -- nobody would pry into his business," Nehrenz said.

"We're a small, tight-knit community but they're not all up in everybody else's business unless you want them to be.