Perth woman Janette Henry once considered the girlfriend of Las Vegas gunman Stephen Paddock, Marilou Danley, to be family.
She says the shooter's girlfriend was married to her father a long time ago, but the Koondoola woman hasn't seen her stepmother for 20 years.
"I could be wrong but I don't think she had anything to do with it," Ms Henry told 7 News.
Thirty years ago, Marilou Danley loved another man, Janette Henry's father, who has since passed away.
In the years afterwards, the charity worker kept in touch with Marilou.
Janette can't fathom how the woman her father once loved has found herself caught up in the shooting tragedy.
"People need answers and if she has the answers, then so be it," she said.
Marilou Danley has been questioned by the FBI after flying back from the Philippines on Wednesday.
Police are now working on two new theories.
They believe the shooter could have had an accomplice as well as a plan to escape, rather than die inside the Mandalay Bay Hotel.
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Marilou Danley has yet to speak to the media directly, but released a statement through her lawyer.
"I knew Stephen Paddock as a kind caring quiet man. I loved him and hoped for a quiet future together with him," her lawyer said.