US doctor Thomas Chris Lang, charged with murdering his Brisbane lover and leaving a knife embedded in her abdomen has been found guilty for the second time.

Lang, now 68, denied murdering socialite Maureen Boyce whose bloodied body was discovered in her Kangaroo Point penthouse on the morning of October 22, 2015.

But after three days of deliberation following a two-week retrial, a Brisbane Supreme Court jury on Monday delivered a guilty verdict.

When asked if he had anything to say after the verdict, Lang said: “Yes, because I didn’t do it.”

Outside the court, family members embraced after the verdict that came more than five years after Ms Boyce’s death – but not everyone was satisfied with the result.

A lifelong friend of both Lang and Ms Boyce broke down in tears and confronted detectives, saying they would “rot in hell”.

“I am terribly, terribly disappointed. I met Dr Lang with Maureen … he loved her to bits. He was the love of her life. He is a lovely man, he wouldn’t kill a fly,” Jocelyn Banks told AAP outside court.

“They were madly, madly in love. To think that anyone could believe he had done this is beyond comprehension.

“She was the one who tracked him down – it’s a tragic second-time-around love story.”

Lang’s first conviction in 2017 over his lover’s death was quashed on appeal.

The former fashion model and mother of two was stabbed five times with such force that the blade pierced the blood-stained bedding beneath her three times.

“She was found with a kitchen knife embedded in her abdomen down to the hilt,” crown prosecutor Todd Fuller told the jury.

“The tip of which had penetrated through to her back, on the opposite side into the sheet on the bed below her.”

Lang was the only other person in the apartment on the night she died, and the jury rejected his claims that Boyce committed suicide.

Instead, it found Lang stabbed Boyce in a jealous rage after she threatened to “hook up” with an ex-boyfriend.

Lang told police it was like a “stab to the heart” to discover she was still in contact with her former lover.

n sentencing, Justice Ann Lyons said Lang had lied about the critical events leading up to the “vicious attack”.

“You killed a defenceless woman who was most likely fast asleep in her own bedroom,” Lyons said.

“Her family have been deprived of her vibrancy and her love. It is a cause of great sadness that she will never get to meet her grandchildren.”

She sentenced Lang to a maximum life sentence.

Boyce and Lang had known each other for more than 30 years and had indulged in an extramarital affair in the United States in the 1970s.

When Boyce returned to Australia, she was pregnant with Lang’s son who she raised with husband Graham.

Fuller said Boyce told Lang about his son in 2013 and the pair rekindled their relationship in the years leading up to her death.

Lang claimed the pair were engaged and intended to wed before Christmas.

Boyce had been depressed in the days before her death, and the Crown conceded she had struggled with mental illness all her life.