Melissa Beowulf, 61, and her sons Thorsten, 33, and Bjorn Beowulf, 31, are accused of murdering their family matriarch, Mrs Beowulf's mother in law Katherine Panin, 82.

They have pleaded not guilty.

In the conversations, Mrs Beowulf and her sons speculate about a police investigation into Mrs Panin's death and express a belief  her late husband's live-in partner was "stirring trouble".

The trial has heard how Mrs Beowulf's late husband Thorhammer Beowulf had a second partner Dianne McGowan and the unconventional family unit had lived together for years.

But when Mr Beowulf died in 2015 relations soured, and even more so after Mrs Panin died.

A month or so after Mrs Panin's death on October 12, 2015, from what was reported to be a fall down the stairs, police began a homicide investigation and for months secretly recorded the family's conversations.

The covertly recorded audio played to the jury on Tuesday reveal a bitter relationship between Mrs Beowulf and her four sons, and Dr McGowan and her son.

The jury has already heard that Dr McGowan had demanded the return of certain items from the Beowulfs, including a red Persian rug.

She had also made a claim against Mrs Panin’s estate, which later paid out $400,000 to her and her son.

The rug is significant to the Crown case, and prosecutors allege the accused hid the rug before dry cleaning it in an attempt to cover up the alleged crime.

The court has also heard evidence Thorsten Beowulf threw up on the rug when he found Mrs Panin dead.

In relation to the rug, Mrs Beowulf said they should give it back to her "with chunder on it”.

In another conversation, Mrs Beowulf asks Thorsten Beowulf what he wanted to do about the rug.

Mrs Beowulf said she didn't care if it didn't work - in reference to advice that dry cleaning could destroy the rug - but to just get it dry cleaned.

Thorsten Beowulf in a separate conversation calls Bjorn Beowulf and asks him to take it to the dry cleaners.

Bjorn Beowulf agrees and says "I was thinking of just f--king burning it to be honest".

Mrs Beowulf at one point, after receiving a phone call from police who gave her an update on the coronial report, suggested to a son that Dr McGowan was stirring up trouble.

Mrs Beowulf said Mrs Panin fell over twice that day and was running in and out of the garden.

She and one son - which son was not clear from the audio but the jury has transcripts of the recording - discuss the low conviction rates for murder and Mrs Beowulf suggests it was 5 per cent.

“And they can’t rule out accident, how can they pursue a murder inquiry?” the son says.

Mrs Beowulf said she yelled out to Mrs Panin that they were going that day but didn’t check on her, and went on to say how the older woman was irritating but that she still tried to care for her.

Bjorn Beowulf said in another conversation that they could call Dr McGowan to account once it's "revealed to be bullshit".

"There's nothing, there's just nothing there," he said.

The trial continues.