Las Vegas shooter Stephen Paddock sent up to $100,000 to an account in the Philippines - the home country of his girlfriend Marilou Danley - just days before he launched his killing spree, detectives have discovered.

Danley has since returned to the US from a holiday in her homeland and was met by FBI agents at an airport in Los Angeles, where she is co-operating with investigators.

As police scramble to identify a motive for the attack that killed at least 59 people and injured 527, officers have focused on financial transactions carried out by the 64-year-old retired accountant who loved to gamble. A definitive answer as to why Paddock fired into a crowd of 22,000 country music fans attending a festival has so far proved elusive, despite new details emerging about the mechanics of the attack.

In the last three years, more than 200 reports about Paddock’s activities, particularly large transactions at casinos, have been filed with the authorities, according to media reports. While some mentioned “suspicious activity”, others were simply currency transaction reports that casinos are obliged to file when a customer withdraws or deposits more than $10,000 in cash.

Police have said they are searching four crime scenes (AP)

As residents in Mesquite, a retirement community 80 miles from Las Vegas where Paddock lived and planned Sunday’s attack, expressed bewilderment that the killer lived among them, detectives dug deep into his financial history, desperate for any sort of clue.

NBC News reported Paddock had wired $100,000 to the account in the Philippines last week. Officials have confirmed that Marilou Danley, 62, who lived with Paddock in Mesquite, was in the Philippines on Sunday, it was not known whether the money was for her or another purpose.

At a press conference, Las Vegas Sheriff Joseph Lombardo named Ms Danley as a “person of interest.”

Investigators had been speaking with Ms Danley prior to her arrival from the Philippines and say, “we anticipate some information from her shortly."

There were also reports that Paddock had gambled with at least $160,000 in recent weeks in Las Vegas casinos - with 16 separate reports of $10,000 being withdrawn or deposited in a day, with some days showing multiple transactions.

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Yet while officials have been able to provide considerable detail about how Paddock carried out the massacre, for all the resources that have been dedicated to the investigation, they have little to say about why he did so.

That trend continued on Tuesday, with authorities filling in some more detail about the mass shooting - with Mr Lombardo saying that Paddock had fired at a progressively rapid rate for nine minutes after the first 911 call as he rained bullets onto the crowd below.

Mr Lombardo said that all but three of the 59 dead had now been identified and, after a search at a property owned by Paddock in Reno, he said police had found five handguns, two shotguns, a "plethora of ammo" and a number of electrical devices.

That makes 49 guns found in connection to Paddock so far. Police have said they recovered 23 weapons and "bump stock" devices — used to let rifles fire continuously — from the suite Paddock booked on the 32nd floor of the Mandalay Bay casino and hotel located on the Las Vegas Strip. It was out of two windows in that suite that Paddock fired on the crowd attending the Route 91 Harvest Festival nearby before killing himself. Authorities also found 19 guns from his house in Mesquite, along with what officers said were explosives and thousands of rounds of ammo. That is in addition to a supply of ammonium nitrate, which can be used to create explosives, in Paddock's car.

Mr Lombardo made clear that Paddock planned his massacre so meticulously that he even set up cameras inside his hotel room and outside his door, apparently to spot anyone coming for him, the sheriff said.

The cameras Paddock set up at the Mandalay Bay hotel casino were part of the extensive preparations that included stockpiling the nearly two dozen guns and two tripods before opening fire from his perch.

“I anticipate he was looking for anybody coming to take him into custody,” Mr Lombardo said of the cameras.

“The fact that he had the type of weaponry and amount of weaponry in that room, it was preplanned extensively,” the sheriff added, “and I'm pretty sure he evaluated everything that he did and his actions, which is troublesome.”

Mr Lombardo said he is “absolutely” confident authorities will find out what motivated Paddock, but the investigation is proceeding cautiously in case criminal charges are warranted against someone else.

“This investigation is not ended with the demise of Mr. Paddock,” the sheriff said. “Did this person get radicalised unbeknownst to us? And we want to identify that source.”

Reuters said one senior US homeland security official said there were no evidence that Paddock had links to international or domestic terror groups.

Marilou Danley (LVMPD)

“We cannot even rule out mental illness or some form of brain damage, although there’s no evidence of that, either,” the official said.

Some investigators turned their focus from the shooter's perch to the festival grounds where his victims fell. A dozen investigators, most in FBI jackets and all wearing blue booties to avoid contaminating the scene, documented evidence at the site where gunfire rained down and country music gave way to screams of pain and terror.

“Shoes, baby strollers, chairs, sunglasses, purses. The whole field was just littered with things,” said Nevada Attorney General Adam Laxalt, who told The Associated Press it was like a “war zone.” “There were bloodstains everywhere.”

As for Paddock's background, he had a business degree from Cal State Northridge. In the 1970s and '80s, he worked as a mail carrier and an IRS agent and held down in an auditing division of the Defense Department, according to the government. He later worked for a defense contractor.

He had no known criminal record, and public records showed no signs of financial troubles,

Nevada's Gaming Control Board said it will pass along records compiled on Paddock and his girlfriend to investigators.

His brother, Eric, has also been unable to provide any genuine insight into what led to the attack.

Las Vegas shooting – in pictures Show all 15 1 /15 Las Vegas shooting – in pictures Las Vegas shooting – in pictures People scramble for shelter at the Route 91 Harvest country music festival after gun fire was heard Getty Las Vegas shooting – in pictures People carry a person at the Route 91 Harvest country music festival after shots were fired David Becker/Getty Las Vegas shooting – in pictures People run from the Route 91 Harvest country music festival after gun fire was heard David Becker/Getty Las Vegas shooting – in pictures A handout photo released via Twitter by Eiki Hrafnsson (@EirikurH) showing concertgoers running away from the scene (C) after shots range out at the Route 91 Harvest festival on Las Vegas Boulevard EPA/Eiki Hrafnsson Las Vegas shooting – in pictures People lie on the ground at the Route 91 Harvest country music festival after hearing gun fire Getty Las Vegas shooting – in pictures A man in a wheelchair is taken away from the Route 91 Harvest country music festival after hearing gun fire David Becker/Getty Las Vegas shooting – in pictures People stand on the street outside the Mandalay Bay hotel near the scene of the Route 91 Harvest festival on Las Vegas Boulevard EPA/Paul Buck Las Vegas shooting – in pictures FBI agents confer in front of the Tropicana hotel-casino after a mass shooting during a music festival on the Las Vegas Strip Reuters/Las Vegas Sun/Steve Marcus Las Vegas shooting – in pictures Las Vegas police run by a banner on the fence at the Route 91 Harvest country music festival grounds after shots were fired David Becker/Getty Las Vegas shooting – in pictures An injured person is tended to in the intersection of Tropicana Ave. and Las Vegas Boulevard after a mass shooting at a country music festival Ethan Miller/Getty Las Vegas shooting – in pictures Metro Police officers pass by the front of the Tropicana hotel-casino after a mass shooting at a music festival on the Las Vegas Strip Reuters/Las Vegas Sun/Steve Marcus Las Vegas shooting – in pictures A woman sits on a curb at the scene of a shooting outside of a music festival along the Las Vegas Strip AP/John Locher Las Vegas shooting – in pictures A cowboy hat lays in the street after shots were fired near a country music festival in Las Vegas Getty Las Vegas shooting – in pictures Las Vegas Metro Police and medical workers stage in the intersection of Tropicana Avenue and Las Vegas Boulevard South after a mass shooting at a music festival on the Las Vegas Strip Reuters/Las Vegas Sun/Steve Marcus Las Vegas shooting – in pictures Sheriff Joe Lombardo (2-R) speaking during a press briefing in the aftermath of the active shooter incident on Las Vegas Boulevard EPA

“It just makes less sense the more we use any kind of reason to figure it out,” he said in text message sent to the news agency. “I will bet any amount of money that they will not find any link to anything...he did this completely by himself.”

He described his brother as a financially well-off enthusiast of video poker and cruises, with no history of mental health issues. Reports said that several decades ago, Paddock worked as a postal delivery clerk and an agent for the Internal Revenue Service.

President Donald Trump, who is due to visit Las Vegas on Wednesday, told reporters Paddock had been “a sick man, a demented man”. He declined to answer a question about whether he considered the attack an act of domestic terrorism.

“He’s a sick man, a demented man. A lot of problems, I guess,” Mr Trump told reporters before boarding his Marine One helicopter on his his way to hurricane-ravaged Puerto Rico on a one-day trip.

“We are looking into him very, very seriously. But we’re dealing with a very, very sick individual,” the President added.

The shooting has reignited the controversy over gun ownership laws, but the White House and Republicans have brushed aside attempts to discuss gun policy.

When asked whether the Las Vegas shooting would prompt him to take up gun control legislation, Mr Trump responded: “Look, we have a tragedy. What happened is, in many ways, a miracle.”