Prosecutors in Western Australia have called for a severe sentence for an elderly, wealthy Albany businessman who attempted to hire a hitman to murder his son’s ex-wife.

Brian Vincent Attwell, 73, was found guilty by a jury after a five-day trial in the Albany Courthouse on the state’s southern coast in November, charged with the rare offence of attempting to procure the commission of a crime.

The court heard the accused had asked a truck driver, who approached him desperate for work with his civil contracting company AD Contractors, to kill 50-year-old Michelle Patreena Attwell after becoming frustrated with a protracted, bitter legal dispute between her and his son following the breakdown of their marriage.

The driver informed police, who instructed him to set up a meeting between Attwell and an undercover policeman.

Attwell met the policeman twice at a beach near the woman’s home, and paid $10,000 in two instalments as a down payment on a $30,000 job, telling the officer to bind the “maggot” in duct tape, strangle her and bury her in a 30-foot hole dug by an excavator.

On Friday in WA’s Court of Appeal, prosecutor James MacTaggart said that Attwell’s conduct – “crudely plotting the death of someone who was once a member of the offender’s family” because of the legal dispute – was “not on” and “must be visited with a very severe deterrent sentence”.

“It cannot be the case that the justice system of this state is undermined in such a violent fashion,” Mr MacTaggart said.

He said the undercover policeman did not say anything about a hit when he made initial contact, merely saying he had been asked to meet with Attwell.

“This is not a case where the offender was encouraged … to commit an offence.”

But defence lawyer Tom Percy suggested Attwell’s comments about getting “rid of” his former daughter-in-law were “throwaway” and that he may not have taken the matter further had he not been contacted by the undercover officer after the tip-off from the driver.

“The whole idea may have died a death,” he said.

“None of it ever went beyond speculation.”

Mr MacTaggart said Attwell made it clear to the undercover officer that he didn’t want any trace of evidence that linked the crime back to him, saying the body shouldn’t be buried on his land as local police knew of his antipathy towards the intended victim, and he wanted “no blood”.

Mr Percy called for a jail term of less than five years, which under WA can be suspended, saying Attwell’s health would deteriorate faster if he was jailed.

Attwell had already spent a significant amount of time in jail after he was arrested and his behaviour while on bail had been exemplary, Mr Percy said.

“He’s heard the clanging of gates – he’s been in prison,” the QC said.

Referring to the victim impact statement, Mr MacTaggart said Ms Attwell had been immensely frightened by her ordeal – not even even listening to music so she could hear if someone was approaching her house.

Justice Ralph Simmonds will sentence Attwell on Tuesday.