Police said Robert Crawford called triple zero, was the last person to see his wife alive and was at the property on the night she died.
He is assisting police, who have not confirmed that he is a suspect.
Police have appealed for public information, including from multiple women they believe have had contact with Crawford.
“We believe there are women who were involved in relationships with Mr Crawford who may have information about Frances that will assist with this investigation,” Detective Superintendent George Marchesini told reporters.
“Mr Crawford may have met these women on dating applications and through his personal and professional life.
“We can say that Mr Crawford has connected with women nationally and internationally.”
Crawford had allegedly met with women in Italy, the United States, Papua New Guinea, Guam, Afghanistan, Japan, Malaysia and New Zealand.
Closer to home, he also allegedly connected with women in Western Australia, the Australian Capital Territory, Northern Territory (Act), New South Wales, Victoria and his own state of Queensland.
“The purpose of today is to appeal for public assistance as investigations continue into the circumstances,” Marchesini said.
“We’re confident that there are people who are out there who have vital information.”
Frances’ death was initially deemed suspicious.
“We are now alleging that she was murdered,” Marchesini said.
Police said Crawford had located his wife’s body in the early hours before calling emergency services.
Asked if he thought it was unusual Frances might have been using a mower at 3am, Marchesini said: “Emergency services have attended at that time.
“Any situation like that, police are going to undertake further investigation.
“There’s been extensive forensic testing … as a result of that we can’t, at this stage, definitively determine how she has come to be at the bottom of that retaining wall.”
No domestic violence orders were in place when Frances died but police had attended the property in July last year.
“That was in regards to a call for service in regards to domestic and family violence,” Marchesini said.
Police said Frances’ family were “looking for answers”.
