A woman allegedly murdered in a staged lawnmower crash was due to receive a favourable financial settlement if she acted on her plan to divorce her unfaithful husband, a jury has heard.

Robert John Crawford is accused of murdering his wife Frances by strangulation at the couple’s property west of Brisbane in the early hours of July 30, 2024.

Crawford, 49, faced losing the couple’s $2 million bush block house and his RAAF senior pilot’s superannuation in a marriage separation brought on by his serial infidelities, prosecutors claimed.

He pleaded not guilty to murder at his Brisbane Supreme Court trial, which began in October.

Crawford claims his wife died from crushing injuries or traumatic asphyxia after being caught under the lawnmower’s steering wheel while moving the vehicle away from automated lawn sprinklers.

Lawyer Meagan Murrell testified on Tuesday that Ms Crawford contacted her in July 2023 after the couple temporarily separated and her husband broke into the family home.

“She was concerned Robert had been cheating on her for a decade. She was concerned about contracting a sexually transmitted disease,” Ms Murrell said.

The family law expert agreed with prosecutor Chris Cook there was a “huge disparity” in the couple’s income.

Crawford made about $200,000 annually, while his wife earned $500 per week and had little superannuation.

The alleged victim was also concerned her husband would take money from their accounts and had already done so to pay for his own solicitor, the jury heard.

“He took $6000 from our funds and left me with $150,” Ms Crawford texted to Ms Murrell.

“I told her there would be a financial settlement assessment alteration in her favour,” the family lawyer told the court.

Ms Crawford went back and forth on her decision to leave her husband, at one point texting Ms Murrell that her marriage “needs finality”, the jury heard.

She asked Ms Murrell to keep her file open but was trying to reconcile with her husband in their last conversation in May 2024.

Ms Crawford’s body was found by paramedics at the bottom of a retaining wall near an overturned ride-on lawnmower after her husband called triple zero at 3.38am and attempted to resuscitate his wife.

The 49-year-old psychologist and mother-of-three was declared dead at the scene.

Senior Sergeant Stephen Coote, from Queensland Police’s forensic crash unit, testified he had tested the lawnmower multiple times, including on the morning Ms Crawford died.

“Was there a very early concern that the crash was staged for homicide?” defence barrister Saul Holt asked.

“There were suspicions,” Sen Sgt Coote said.

Police formed the opinion the lawnmower was reversing with its headlights off when it went over a retaining wall, the jury heard.

“It was moving backward … there were scrape marks on the underside of the mower’s cutting deck and damage to a support strut at the rear of the mower,” Sen Sgt Coote said.

“The reverse was very slow.”

The mower was later tested in a Toowoomba towing company’s shed on two occasions in September, the jury heard.

The ride-on had been found at the property on a setting in which it would have started and run the engine without headlights being activated, the jury heard.

They were shown photos of the mower overturned on a concrete floor with its steering wheel unable to touch the ground.

“The steering wheel was plastic and coated with rubber … it was not deformed in any way,” Sen Sgt Coote said.

The jury heard there was a safety switch under the mower’s seat, but there was a problem with its connection and it didn’t always work.

The trial continues.