Kiwi mum Ngatokoona Mareiti jailed over 'toolbox murders' in Australia

A Kiwi mother of seven who cleaned an apartment where a couple were tortured and listened as they screamed from inside the metal toolbox that would become their grave has been jailed for manslaughter.

Ngatokoona Mareiti, 40, didn't play a role in the murder of Cory Breton, 28, and Iuliana Triscaru, 31, at a lagoon on Scrubby Creek in Kingston, Queensland in January 2016.

But she did see them, bleeding and with hands bound, when she visited a home to buy drugs, the Brisbane Supreme Court heard.

Iuliana Triscaru, 31, and Cory Breton, 28, were found dumped inside a metal toolbox. Photo / Supplied

Prosecutor David Meredith told the court: "They'd obviously been assaulted and interrogated by other accused."

"She would have noticed Breton was bleeding from the mouth.'

Mareiti later heard the murdered couple screaming from inside the toolbox before it was loaded into a ute and dumped into a lagoon.

Then, directed by one of her co-accused, she bought cleaning supplies and cleaned the unit where the couple had been tortured.

Mareiti initially faced double murder charges, before pleading guilty to the lesser charges of manslaughter.

She was jailed for nine years but with time served will be eligible for parole in June next year.

In sentencing Mareiti, Justice David Boddice said Breton and Triscaru died horrible deaths and that Mareiti assisted her co-accused when she "knew that the unlawful killing was a probable consequence".

"It was apparent from the fact they were tied up right from the start that this was a dreadful event," Boddice said.

Police retrieve the metal box from a dam near Scrubby Creek in Kingston in 2016. Photo / News Ltd

"You did nothing about contacting the authorities. You did nothing about attempting to encourage the others to desist in their conduct.

"By your dreadful and, what I consider, despicable deeds, you allowed events to unfold that caused the deaths of these two people."

Mareiti was friends with Triscaru, with their children even playing together, the court heard.

"The decisions [she] made showed a complete lack of human decency in relation to those poor victims," Boddice said.

Triscaru's mother called her a coward, evil and a liar, AAP reported.

"You left her there to be tortured and to be killed ... [you have] turned my life into a forever nightmare," she said in a victim impact report.

"If you had called the police perhaps she would have been alive today."

Mareiti is likely to be deported to New Zealand upon her release from jail.