Queensland Police have launched a murder probe into the mysterious death of a woman in a terrifying lawnmower incident.

It follows paramedics being called to an accident involving a ride-on lawnmower in the Lockyer Valley at 3.40am on July 30.

Frances Elizabeth Crawford, 49, was found dead at the bottom of a steep retaining wall in the backyard of her home in Upper Lockyer.

Police said days later that the death was being treated as suspicious.

On Friday, Queensland Police said the investigation had become a homicide probe, as examination of the circumstances that lead to the death of the 49-year-old psychologist continued.

Key to the investigation are the “relationships” of Crawford’s husband, Robert, with unknown women in Australia and overseas.

“We are particularly interested in speaking with people who knew of Frances or Robert Crawford and their personal circumstances, including their marriage,” regional crime coordinator Detective Superintendent George Marchesini said.

Robert Crawford, who is reportedly an Royal Australian Air Force Squadron Leader based out of the nearby Amberley Airforce Base, has not been charged.

“We believe there were women who were involved in relationships with Mr Crawford who may have information about Mrs Crawford that will assist with this investigation. Mr Crawford may have met these women on dating applications, and through his personal and professional life,” Marchesini said.

“Investigations have revealed Mr Crawford has connected with women in Italy, United States of America, Papua New Guinea, Guam, Afghanistan, Japan, Malaysia, New Zealand, Western Australia, ACT, Northern Territory, NSW, Victoria, and Queensland.”

Asked if Robert Crawford was a suspect in his wife’s death, Marchesini said only that the investigation remained “active”.

“Obviously, Mr Crawford was at the location that night, had called emergency services and has assisted police to this date,” he said.

“There’s been extensive forensic testing and that includes pathology testing and, as a result of that, we can’t at this stage definitively determine how she’s come to be at the bottom of that retaining wall, and it remains subject to the investigation.”

Police said earlier that they did not believe it was a random attack.

“Any information that comes to hand, we will investigate,” Marchesini said.

He said the months since Crawford’s death had been “extremely challenging for [her] family and her children, who are desperate for answers”.

“It’s time for those with information, no matter how small, to come forward,” he said.

Police said some people had provided information since their last public appeal, and thanked them for their bravery.