'Breathtakingly evil': Pair pleaded for their lives from sinking toolbox

An Australian court has heard how two drug dealers spent their last moments begging for their lives, locked in a toolbox that was dumped into a lagoon as their killers looked on.

The horrifying case, which has already seen one Kiwi woman sentenced for her role in the killings, entered a new phase this week as one of her co-accused denied murder charges.

Tuhirangi-Thomas Tahiata, 28, appeared in the Brisbane Supreme Court to deny murdering Cory Breton and Iuliana Triscaru at Scrubby Creek in Queensland on January 24, 2016.

However, prosecutor David Meredith says Tahiata drove the ute that carried Breton and Triscaru to the lagoon from a nearby drug house, AAP reports.

The prosecution also alleges that he handed a claw hammer to one of his co-accused so he could smash holes in the toolbox before it was pushed into the water.

Meredith said in his opening address yesterday that the killings were a "breathtakingly evil act", telling the court that Breton and Triscaru were lured to a two-storey unit on Juers St in Kingston, where they were tied up and tortured before they were forced into the box.

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

Tahiata and one of his co-accused then allegedly drove Tahiata's Toyota Hilux ute, carrying the toolbox, to a nearby quarry where they found the gates locked.

Tahiata's co-accused then suggested they take it to Scrubby Creek.

Meredith said Tahiata initially denied his involvement in the deaths before eventually confessing and taking police to the site, AAP reported.

Police later used a crane to remove the box containing the pair's decomposing remains from the water.

The court heard that their deaths were caused by drowning or suffocation.

After he was charged, Tahiata changed his story and said he wasn't "going to take the blame for what other people had done".

The trial continues today.

"Despicable deeds"

Kiwi woman Ngatokoona Mareiti was sentenced to nine years in prison in December last year for her role in the killings after she pleaded guilty to manslaughter.

The Brisbane Supreme Court heard how the mother of seven cleaned the apartment where the couple was tortured and listened as they screamed from inside the metal toolbox that would become their grave.

Mareiti saw the pair, bleeding and with hands bound, when she visited the home to buy drugs and 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.

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

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.

"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, which could be as early as June this year when she is first eligible for parole due to time served.