Las Vegas gunman Stephen Paddock's "regular companion" was an Australian woman who moved to the United States 20 years ago to work on the casino strip, the government confirmed Tuesday.
Marilou Danley, 62, was initially said to be a "person of interest" but has since been cleared of any involvement in the shocking shooting that left 59 dead and more than 500 injured.
American authorities said she was out of the country at the time retired accountant Paddock, 64, unleashed his reign of terror on concert-goers from a hotel window.
Australian Foreign Minister Julie Bishop tweeted: "I understand US authorities have ruled out Australian Marilou Danley as a person of interest."
She added to reporters that "US authorities were in contact with us about Marilou Danley".
"There are reports her ID was used for booking the hotel or some such detail. Australia will support the US authorities in their investigation in whatever way we can, but we have not had contact with Marilou Danley directly."
US reports and officials said she is either in the Philippines or Japan, although neither country was able to confirm her whereabouts.
Australian media said she was on holiday in the Philippines with three girlfriends.
News Corp Australia newspapers said the Filipino-Australian used to live on the Gold Coast tourist strip and still had a sister there.
"I can't comment at the moment, I can't say anything," her sister Liza Werner told the Sydney Daily Telegraph, which said she was a grandmother.
The newspaper cited friends as saying she resided on the Gold Coast for more than a decade and was married to an Australian man who has since died.
She moved to the US about 20 years ago and reportedly shared a house with Paddock in a new golf course development in the desert just outside Mesquite, Nevada, 80 miles northeast (130 kilometres) of Las Vegas.
It was not clear if they were in a relationship or simply friends, with some reports referring to her as his "regular companion".
Paddock, a high-stakes gambler with no criminal record, killed himself after mowing down concert-goers with burst of automatic weapon fire from the 32nd story window of a swish Las Vegas hotel.
A motive is yet to be established.