Monique Denahy, the Australian mother of two who was planning to flee to Geelong in Victoria, suffered a violent death in Florida at the hands of her former American partner.
Palm Beach County sheriffs concluded Ms Denahy, 49, was strangled by Daniel Millner, 55, before Millner shot himself.
Their bodies were found in a home located inside a gated community in Florida on Saturday, with Ms Denahy's death sparking sadness and outrage, including in Canberra where Liberal MP Sarah Henderson fought back tears during a speech about her "vivacious" and "gentle" friend.
"It was a murder-suicide," Teri Barbera, of the Palm Beach County Sheriff's Office, told AAP on Wednesday.
"The person who committed that murder killed himself.
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"He strangled her and shot himself."
Ms Henderson, in her late-night address to federal parliament on Tuesday, the eve of White Ribbon Day, said Ms Denahy had decided to leave Millner and return to Australia, "but she never made it".
The story highlighted how the cycle of domestic violence needed to be broken, the MP said.
The sheriff's office said there was no documented history of domestic violence between Ms Denahy and Millner, who reportedly was a real estate agent in the Palm Beach area.
Ms Henderson said Ms Denahy's two children, Sam and Zara, were "devastated and shattered beyond words".
* National domestic violence helpline: 1800 737 732 or 1800RESPECT. In an emergency call triple-zero.
* Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14 or the MensLine Australia 1300 78 99 78
