Pepita and Robert Ridgeway pictured on the Sunshine Coast in 2001.
Pepita and Robert Ridgeway pictured on the Sunshine Coast in 2001. Noosa News

Death plot gas allegations disputed at scientist's trial

BOXED in. Finances in peril. Marriage in tatters.

That's how prosecutor David Finch described the life of Sunshine Coast scientist Robert Wayne Ridgeway.

Mr Ridgeway has pleaded not guilty to a charge of attempted murder of his wife Pepita.

And on Thursday, his defence barrister claimed "woefully” bad police inquiries fixated on a "rather inelegant structure” Mr Ridgeway built in 2016.

A hose found duct-taped in the caravan was simply a drain, not a gas dispersal system, the defence said.

At Brisbane Supreme Court, Mr Ridgeway rejected claims he faced an "inexorable”, costly divorce.

"Your relationship was terminally in decline,” Mr Finch told him.

The couple had properties in Queensland and the USA, complicating any possible divorce, the prosecutor said.

"I have so many houses, what would it matter?” Mr Ridgeway replied.

Mr Finch said Mr Ridgeway was the sole beneficiary under his wife's will.

The Crown alleged he tried asphyxiating his wife with the nitrogen apparatus as she slept.

But Mrs Ridgeway allegedly woke up to "hissing and gurgling” gas, and called police.

"I suggest you failed ... because you got the calculations wrong,” Mr Finch told Mr Ridgeway.

Jurors heard Mr Ridgeway worked with nitrogen for decades.

Mr Finch suggested the scientist could have erred because his expertise was electronics, not gas.

Defence counsel Catherine Cuthbert said Mrs Ridgeway wanted her husband "off the property”.

Mrs Ridgeway used domestic violence claims to advance that goal, Ms Cuthbert said, but "overplayed her hand with the gas allegation”.

Ms Cuthbert said marital conflict existed but there was no proof her client saw murder as a solution.

"Bring the evidence that things were desperate,” Ms Cuthbert said in her closing address.

"It smacks of the Crown desperately seeking a motive for a crime that never happened.”

She said "woefully inadequate” investigations meant nobody knew if a garden hose was long enough to connect the nitrogen cylinder to the caravan.

Presumably if Mr Ridgeway wanted to kill, "he wanted to get away with it as well,” Ms Cuthbert added.

But anyone intent on covering their tracks could not dismantle the gas apparatus quickly, she said.

The trial continues. -NewsRegional