Brisbane socialite Maureen Boyce's son has told a jury she wanted her alleged killer to leave her apartment and go back to New Zealand before she died.

Thomas Chris Lang has pleaded not guilty to killing his former lover, who was stabbed multiple times and found impaled to her bed with a cooking knife in her multimillion-dollar Kangaroo Point apartment on October 22, 2015.

Ms Boyce's son Zachary Boyce told the Brisbane Supreme Court today he knew Lang had been staying in her penthouse leading up to her death.

NZ doctor accused of murder


Jurors were shown text messages in which the former model told Dr Boyce she wanted him gone, just three days after he arrived.

"I'm trying to get Tom to go back to NZ ASAP," she wrote on October 13, 2015.

Although he didn't agree with Lang visiting, even sending her a text message saying it was "disgusting" she had someone there when her husband Graham was sick in Cairns, Dr Boyce said he also spoke to her about him on the phone.

"She asked if I would come up to get rid of him, but I said I didn't really want to get involved at that time, didn't want to see him," he told the court.

Thomas Lang is appearing in court, charged with Boyce's murder. Photo / Newscorp
Thomas Lang is appearing in court, charged with Boyce's murder. Photo / Newscorp

The court heard Dr Boyce, a dermatologist, had been previously told by his mother that Lang was his biological father, but no DNA testing had ever been done.

Dr Boyce, who was "very close" to his mother, said she had depression for the two years leading up to August 2015.

"I saw her make a dramatic recovery and change in her mood," he said.

Dr Boyce told the court they went to see Strictly Ballroom the musical days before she died, something she wouldn't have done when she was depressed.

He said she told him that night "she was so glad she could get away from Tom for the night".

Dr Boyce said he spoke to her the night she died and told him she'd had a wonderful dinner with Lang.

Crown prosecutor David Meredith told the jury in his opening address yesterday that Ms Boyce was in a relationship with Lang while he was a doctor in Texas in the 1980s and she was modelling in the US.

He said she came back to Australia to be with her husband, but later told Lang that her son Zac was his child.

The pair rekindled their relationship in 2013 while Lang was a doctor based in New Zealand, and he was visiting Ms Boyce at her home in 2015 when she died

Meredith said Lang's interviews with police would show he claimed Ms Boyce had been distressed, they had argued and she had thrown her mobile phone off the balcony.

The jury is being asked to consider whether Ms Boyce committed suicide or if she was killed by Lang.