Three men accused of murder allegedly played music to conceal the noise of two people banging from inside a toolbox before it was submerged in water, a jury has heard.
Stou Daniels, Davy Malu Junior Taiao and Trent Michael Thrupp are charged with murdering Cory Breton, 28, and Iuliana Triscaru, 31, on January 24, 2016.
All three men pleaded not guilty to two murder charges at the start of their trial in the Queensland Supreme Court on Monday.
Crown prosecutor Nathan Crane told the jury Mr Breton and Ms Triscaru were lured to a residential unit at Kingston, south of Brisbane, and tortured over the course of a day before being forced into a large toolbox.
"The transition of the toolbox to a HiLux utility vehicle attracted attention from those present at the unit complex. There was noise emanating from the toolbox," Mr Crane said.
"There was music used from the HiLux to cover up the sound.
"Various residents can tell you what they heard from the back of the utility in the car park."
Evidence that Mr Breton and Ms Triscaru were still alive when they left the unit would come from the testimony of multiple witnesses about hearing banging noises from the toolbox, Mr Crane said.
"They were still trying to get out," he said.
Mr Crane told the jury Mr Breton and Ms Triscaru were assaulted, interrogated and threatened with harm from knives and guns over a dispute involving drug dealing before they died.
"It was torturous. They were assaulted when they arrived and throughout the day ... while bound with cable ties and duct tape," Mr Crane said.
Mr Crane said the pair was forced into a toolbox two metres long and 60 centimetres deep that was driven to nearby Scrubby Creek on the back of the HiLux.
"They were likely alive in the toolbox when they entered the body of water at Scrubby Creek."
Police divers found the bodies of Mr Breton and Ms Triscaru in the box at the bottom of the lagoon two weeks later.
"It was obvious there were attempts to weigh the toolbox down. There were pieces of concrete and old tyres in the same vicinity," Mr Crane said.
The bodies were so decomposed doctors could only conclude the pair died either from asphyxiation before being put into the water, or from drowning.
The jury was shown images of the black toolbox being lifted from the lagoon strewn with weeds and water lilies.
Justice Glenn Martin told the jury Daniels, Taiao and Thrupp had previously faced trial for the murder of Mr Breton and Ms Triscaru.
"That this is a retrial has nothing to do with your task," Justice Martin told the jury.
Mr Crane said the prosecution case was Thrupp was at least present when the toolbox was dumped into the water.
Daniels and Taiao were also responsible for the murders because of their actions immediately beforehand, he told the jury.
"The violence, their taking away of the toolbox, made them just as liable," Mr Crane said.
The jury heard Mr Breton and Ms Triscaru were good friends and were involved in drug dealing.
"Drugs are at the heart of this. The motivation for it ... the catalyst for the killings," Mr Crane said.
He told the jury the Kingston unit was thoroughly cleaned with all furniture removed after Mr Breton and Ms Triscaru disappeared.
The jury was shown text messages allegedly between Thrupp and Daniels discussing the extensive police search around Kingston and the potential need for legal advice.
Defence barristers for Daniels, Taiao and Thrupp are due to give their opening addresses to the jury on Tuesday.
The trial is scheduled to go for three weeks.
