Pepita Ridgeway leaves court where her husband Robert is on trial for attempted murder.
Pepita Ridgeway leaves court where her husband Robert is on trial for attempted murder. Liam Kidston

Wife's horrific awakening claimed at poison gas trial

HE IS accused of an elaborate plot to kill his wife by poisoning the air she breathed.

Robert Wayne Ridgeway pleaded not guilty on Tuesday to the attempted murder of Pepita Ridgeway, and not guilty to an alternative charge of administering a noxious gas with intent.

Prosecutors claim the physicist and electrical engineer feared his Australian wife would leave him, so he introduced nitrogen to the caravan where she slept at the Sunshine Coast suburb of Doonan on July 5, 2016.

"The noise was coming from just under my pillow," Mrs Ridgeway told Brisbane Supreme Court jurors.

"I was scared. I knew there was something underneath me.

"That's when I lifted up the mattress and could see there was a hose with black tape."

In a 000 call played to the jury, Mrs Ridgeway said: "I'm freaking out because I'm scared he's got a gun, he's American."

Jurors saw an email prosecutors say Mrs Ridgeway sent her husband on July 1, 2016.

"As you know, I have realized that we can no longer be together or live together," it read.

The Crown claimed Mr Ridgeway bought a big nitrogen cylinder on July 4, connecting it to the caravan by hose.

The gas could displace oxygen, causing the wife to be asphyxiated, prosecutor David Finch said.

Before moving to Queensland, the Ridgeways raised three children in America, owning properties in Utah, New Mexico and Colorado.

Mr Finch said any separation would have been tricky, considering the couple's intertwined lives and property interests.

"Pepita Ridegeway's death, her passing, would have brought a swift conclusion to all of that."

Mrs Ridgeway said during a 2011 argument in Las Vegas, her husband yelled at her for about 30 minutes after a disagreement over food.

"He threatened that if I divorced him, he would kill me and the children."

But Mrs Ridgeway was the one "enraged" in one argument, defence counsel Catherine Cuthbert claimed.

She said Mrs Ridgeway "ripped" her husband's headphones off in a June 2016 altercation.

She told Mrs Ridgeway that after police turned up on July 5, "You got your wish and Robert was taken away."

Mrs Ridgeway said the couple argued about money and properties, and her husband also owned a 75-hectare property near Mackay.

"You're not trying to cut him out are you?" Ms Cuthbert asked.

"I'm just trying to survive," Mrs Ridgeway replied.

The trial continues.  -NewsRegional