Investigators have met with the brother of Las Vegas gunman Stephen Paddock as friends and relatives of the victims of the shooting return to reclaim baby strollers, shoes, phones, backpacks and purses left behind in the panic as they fled.

The interviews with Paddock’s brother Eric on Saturday and Sunday were part of an exhaustive search of clues about the 64-year-old unleashed gunfire from broken windows in the 32rd floor of the Mandalay Bay hotel casino, killing 58 and wounding almost 500.

US authorities also continue to talk with Paddock’s girlfriend as they struggle to come up with a motive for his sniper attack from the Mandalay Bay hotel.

Las Vegas Sheriff Joe Lombardo said the FBI are quizzing Marilou Danley, a Filipino-born Australian citizen, about Paddock’s gun purchases, movements and who he came in contact with before the October 1 massacre.

Sheriff Lombardo told reporters they have found no known terrorism links to Paddock.

He said on Tuesday (AEST) that Paddock targeted aviation fuel tanks, stockpiled his car with explosives and had personal protection gear as part of an escape plan, the Clark County sheriff said Monday.

Sheriff Joe Lombardo said at a news conference that they still have not pinpointed the shooter’s motive behind his decision to fire on a concert crowd of 22,000 in Las Vegas on Oct. 1 from the 32nd floor of the Mandalay Bay hotel casino.

Eric Paddock declined to say what he was asked by police, but he said he’s cooperating with investigators, according to the Las Vegas Review-Journal.

“I’m trying to get them to understand Steve’s mindset,” Eric Paddock told the newspaper. “I don’t want them to chase bad leads.”

The personal effects being recovered on Monday were strewn across the massive grassy concert venue where 22,000 country music fans attended the Route 91 Harvest festival.

Eric Paddock said he went to Las Vegas to retrieve his brother’s body in hopes of sending the cremated ashes to their 89-year-old mother in Orlando.

Officials said they could not discuss the results of an autopsy done on Stephen Paddock, who took his own life before officers arrived at his Las Vegas Strip hotel suite.

Eric Paddock told the Review-Journal that he plans to put his brother’s assets in a trust that would benefit the shooting victims.

The family of one of the victims has already asked a Nevada judge to appoint a special administrator to take control of the gunman’s assets, a necessary step to allow lawsuits to be brought against Paddock’s estate.

Meanwhile, the makeshift SWAT team of police officers who made it to Paddock’s door at the Mandalay Bay hotel casino 12 minutes after the first shots were fired described how they got there and the “gun store” they found inside his room.

Officer Dave Newton told CBS 60 Minutes they found “so many guns. So many magazines. Stacks and stacks of magazines everywhere.

“Just in suitcases all neatly stacked against pillars, around the room, all stacked up, rifles placed all throughout. All kinds of monitors and electrical equipment he had in there.

“It just looked like almost a gun store”.

-With AAP