QUESTIONS are being asked about whether the Las Vegas shooter was alone in his hotel suite as originally thought.
Stephen Paddock launched his deadly 72-minute rampage, which killed 59 and injured more than 500, from a room on the 32nd floor of the Mandalay Bay Resort on the famed casino strip.
But a receipt for room service has emerged showing a hefty food order and a note indicating there were two guests inside.
The potential clue was uploaded to Facebook by a man named Tony Hernandez Armenta but later deleted.
It indicates two guests ordered an assortment of items including a burger, bagel, soups and soft drink.
While the receipt says that the meal was for two people, but it's unclear if there actually was another person in the room.
Police previously said that Paddock had also used Marilou Danley's ID when he checked in, which could account for the fact two people were thought to be occupying the room.
The receipt also appears to dispute the timeline of the massacre. Police have previously stated that Paddock checked into the hotel on September 28, but the receipt suggests he was there at least one day earlier.
And another source told journalist Laura Loomer that Paddock was actually checked in as early as September 25.
The curious item emerged as President Donald Trump and first lady Melania Trump met privately with victims of the shooting at a hospital, praising them and the doctors who treated them as he visited a city still reeling from the worst gun massacre in modern US history.
Mr Trump invited survivors to visit him at the White House.
Speaking to reporters from the lobby of the University Medical Centre lobby, Mr Trump said he'd met "some of the most amazing people" and commended the doctors who'd worked to save them for doing an "indescribable" job.
"It makes you very proud to be an American when you see the job that they've done," he said.
The Sunday night rampage injured 527, some from gunfire and some from a chaotic escape.
"It's a very sad thing. We are going to pay our respects and to see the police who have done really a fantastic job in a very short time," Mr Trump told reporters before departing the White House.
He said that authorities were "learning a lot more" about the shooter Stephen Paddock, 64, and it would be "announced at an appropriate time. It's a very, very sad day for me personally."
No cameras were allowed during Mr Trump's meeting with survivors, perhaps to avoid issues he encountered during yesterday's visit to Puerto Rico.
Mr Trump infuriated locals by saying Puerto Ricans should be "very proud" that hundreds of people haven't died after Hurricane Maria as they did in "a real catastrophe like Katrina."
KILLER'S GIRLFRIEND RETURNS
His visit comes as Australian grandmother Marilou Danley was detained by FBI agents for questioning about the Las Vegas massacre as she arrived home to the United States last night.
Ms Danley, 62, was the long-term partner of professional gambler and former accountant Paddock, who on Sunday night became America's worst mass murderer.
She was yesterday formally labelled a "person of interest" in the investigation and authorities have not ruled out a terror link to her birth country, the Philippines, to where Paddock mysteriously wired $US100,000 ($128,000) in the past weeks.
The former Gold Coast resident and Australian passport holder was in the Philippines when Paddock, 64, killed 59 and injured more than 500 country music fans at an outdoor country music festival.
Her brother, Reynaldo Bustos, said he immediately contacted his sister when he saw the news.
"I called her up immediately and she said, 'Relax, we shouldn't worry about it. I'll fix it. Do not panic. I have a clean conscience,'" Mr Bustos told ABC News in his native Tagalog language in the Philippines.
She was initially named in a police appeal for information about her whereabouts in the hours after Paddock was found dead from a self-inflicted gunshot.
Police found her casino-issued identification, known as a "players card", in his room, which was littered with weapons and spent ammunition.
Sheriff Joseph Lombardo later stated Ms Danley had been located overseas and was no longer "a person of interest".
A frequent traveller who regularly returned to Australia, where she has family in Queensland's Gold Coast, Ms Danley left America for Hong Kong on September 25 and was located in the Philippines.
Yesterday, she arrived back, in the US on flight Philippine Airlines 102 and was detained by the FBI at Los Angeles Airport on her return to the US to face questions.
"The investigation with her is ongoing and we anticipate some further information from her shortly," said Sheriff Joseph Lombardo of Clark County, which includes Las Vegas.
"Currently she is a person of interest."
FAMILIES IN SHOCK
Danley's sisters revealed to Channel 7 News the former Gold Coast resident had been put on a flight to the Philippines two weeks before the massacre.
"She didn't even know that she was going to the Philippines until Steve said, 'Marilou, I found you a cheap ticket to the Philippines,'" one of the unnamed women stated.
"She was sent away. She was away so that she will not be there to interfere with what he's planning."
"He sent her away so that he can plan what he is planning without interruptions," one of Danley's sisters said. "In that sense I thank him for sparing my sister's life. But that won't be to compensate the 59 peoples' lives."
The women insisted their sister was "a good person and gentle soul" but suggested she might be able to assist authorities in their investigations.
"No one can put the puzzles together. No one. Except Marilou. Because Steve is not here to talk any more. Only Marilou can maybe help."
Investigators are also looking at a $100,000 wire payment to the Philippines in the week before the massacre.
Paddock's Florida-based brother Eric Paddock yesterday disputed there was anything questionable about the six-figure wire transfer the killer made recently.
"One hundred thousand dollars isn't that huge amount of money," he told media outside his home.
"Condemn Steve for gambling. Steve took care of the people he loved. He made me and my family wealthy."
Eric Paddock has described Ms Danley as a " nice woman" who was Facebook friends with their elderly mother. He said his brother may have "manipulated her so that she was far away from this and had money".
"As he was descending into hell ... he wanted to take care of her," he suggested.
Such behaviour would differ from that portrayed by acquaintances of the couple, who yesterday said they often saw Paddock behaving abusively to his partner.
He was remembered by a cafe owner in his local casino in Mesquite as bullying her.
"It happened a lot," said Esperanza Mendoza in Starbucks.
Ms Mendoza said Paddock would loudly reject Ms Danley's offers to pay for their coffees.
"He would glare down at her and say - with a mean attitude - 'You don't need (a) casino card for this. I'm paying for your drink, just like I'm paying for you,'" she said.
Then she would softly say, 'OK' and step back behind him. He was so rude to her in front of us."
None of Danley's former husbands or her California-based daughter have spoken to media.
SHOOTER REPORTEDLY ON ANTI-ANXIETY MEDICATION
It has also been revealed that the gunman was recently prescribed anti-anxiety medication, a report said.
Paddock purchased 50 10-milligram tablets of Valium - on June 21, the Las Vegas Review-Journal reported, citing records from the Nevada Prescription Monitoring Program.
The prescription was from Henderson general practitioner Dr. Steven Winkler, and his office declined to make him available for comment.
Paddock purchased the drug, without insurance, from a chemist in Reno, Nevada.
Update your news preferences and get the latest news delivered to your inbox.