Toni Leanne Peacock jailed for manslaughter, Cooper Lindsay Millard jailed for murder

After killing his rival in a bizarre love triangle, a murderer plotted with his girlfriend to make the death look like suicide, and for awhile they thought they’d gotten away with it.

For hours after the bloody death of volunteer Fraser Coast firefighter Mark Carson, his killers stayed in his Pacific Haven home, planning how to get away with what they’d done.

Mr Carson, 58, had just enjoyed a coffee with his ex partner, “femme fatale” Toni Leanne Peacock, 43, before her new and jealous lover, Cooper Lindsay Millard, came into the house and all hell broke loose.

Minutes later Mr Carson was dead. The former personal trainer had been stabbed with a screwdriver and his throat had been cut.

His killers tried to make it look like a suicide, and for weeks they thought they’d gotten away with it.

But an intensive police investigation brought them unstuck.

In March 2024, the Maryborough Supreme Court heard how Mr Carson had been murdered by 45-year-old Millard at his Pacific Haven home on April 3, 2021.

After initially pleading their innocence to a charge of murder, Peacock and Millard changed their pleas on the second day of their trial.

Millard pleaded guilty to murder and Peacock pleaded guilty to the lesser charge of manslaughter, which was accepted by the Crown.

During their subsequent sentencing, the court heard details of a deadly love triangle that started when Peacock became involved with Millard near the end of her relationship with Mr Carson, who she’d first met through his role as a personal trainer.

The court heard that for some time before his death, Peacock had expressed the view that Mr Carson ought to be killed or at least seriously injured.

Toni Peacock has been sentenced for the manslaughter of her former partner.

She’d said to another friend, Nathan Jewell: “I just want him dead”.

Peacock began her involvement with Mr Carson after her relationship with the father of her four children broke down in 2017.

She lived with Mr Carson for about a year and the court heard their relationship was “volatile” and she later complained to Mr Jewell of domestic violence.

When their relationship ended, Mr Carson’s mental health was impacted and he received psychological counselling right up to the time of his death.

During that time, Peacock stayed in touch, reigniting their relationship on occasions, the court heard.

In November 2020, she was still in a relationship with Mr Carson when she met Millard, who became “infatuated” with her.

The relationship progressed quickly.

“He was possessive and felt threatened by Mr Carson in the sense that Mr Carson had very recently held your affections,” Justice Peter Davis said in his sentencing remarks.

Later in 2020, Mr Carson broke into Peacock’s home and found her and Millard naked and asleep together in bed. He took a photo of the scene and sent it to her, causing tension, Justice Davis said.

In the lead-up to Mr Carson’s death, Millard and Peacock spoke about wanting Mr Carson hurt or dead.

Pacific Haven murder victim Mark Carson.

In one bizarre instance, Peacock left a voice message on a pig farmer’s phone that they had killed Mr Carson, and asked if they could borrow his pig pen because they needed “the hungry piggy-os”.

An “obviously jealous” Millard brought the subject up more often than Peacock, but their discussions included a plan to kill Mr Carson and make it look like suicide, Justice Davis said.

Throughout this time, Peacock maintained contact with Mr Carson, which angered Millard, he said.

He said Peacock played the role of the “femme fatale”, holding the affection of both men.

The day of Mark Carson’s murder

On April 3, 2021, Peacock and Millard went to Mr Carson’s home at Pacific Haven on the pretence of it being a friendly visit.

Peacock went in first and had a coffee with Mr Carson.

After 40 minutes, she signalled for Millard to come inside and an altercation took place.

Toni Peacock has been sentenced for the manslaughter of her former partner.

Peacock was the first to arm herself, stabbing Mr Carson in the shoulder with a screwdriver.

The court heard Mr Carson “fought for his life” when set upon by the pair.

Millard then used a knife to slash Mr Carson’s throat, a wound they would later try to claim was self-inflicted.

Mr Carson’s death “would have been relatively rapid”, the court heard.

During a call Millard then made to 000, Peacock could be heard in the background calling Mr Carson a “f —king coward” and saying he had taken his own life.

Millard then tried to “strangle” Peacock to leave marks around her neck and used Mr Carson’s nunchucks to “punch” her on the buttocks, which police were to believe occurred in an altercation with her former partner, after which he had slit his own throat.

“All this of course was a pack of lies,” Justice Davis said.

When she went to Mr Carson’s funeral Peacock told the mourners “I didn’t do it”, the court was told.

The plot to get away with it

For six weeks after his death, Millard and Peacock thought they’d gotten away with it.

Millard seemed “proud of himself” after Mr Carson’s death, the court heard, and spoke of feeling “relief and satisfaction”.

He said he had “fooled police” and given an “Oscar-winning performance” in the weeks after the murder, the court was told.

But police were far from convinced.

Unbeknown to the pair, police had placed a listening device in Peacock’s car and in the shed of the home where they lived.

During recorded conversations, police heard how Millard had to fabricate injuries by choking her and punching her in the buttocks with the nunchucks.

On May 18, 2021, the two were arrested and charged.

Toni Peacock has been sentenced for manslaughter after the death of her former partner.

Facing court for sentencing

Barrister Ed Whitton, appearing on behalf of Millard, said the decision to kill Mr Carson was made in “the fog of prolific, long-term methamphetamine use,” which had increased dramatically in the lead-up to the killing.

Mr Whitton said his client was remorseful, but had specifically asked him not to make a huge issue of his personal remorse as he feared that would sound trite.

But Millard deeply regretted what he had done and the suffering he had caused, he said.

Mr Whitton said Millard had been deeply affected by the victim impact statements read out by Mr Carson’s family.

Barrister Kim Bryson, appearing for Peacock, said her client had known she and Millard were going to Mr Carson’s home to cause serious harm, but had not expected it to go as far as it had.

She said Peacock’s statement to Mr Jewell about wanting Mr Carson dead had to be considered in context as she had been confiding in him well before the killing about alleged domestic abuse and while she was “high on drugs”.

She said it was not open for the inference to be drawn that the contemplation of severe harm had started then.

The scene outside the Pacific Haven home on the day of Mark Carson's killing.

Millard was sentenced to life in prison for murder, while Peacock was sentenced to 10 years in prison for manslaughter, of which she must serve eight before being eligible for parole after being declared a serious violent offender.

Mr Davis said it was a serious example of manslaughter.

While Peacock did not inflict the fatal blows and while she did not intend for Mr Carson to die, she must be considered as the reason the plan was hatched, he said.

“Mr Carson was your former partner,” he said.

“Millard had no interest in him whatsoever apart from that fact.”

Toni Leanne Peacock with Cooper Lindsay Millard have both been convicted and sentenced over the death of Pacific Haven's Mark Carson.

A family left devastated

Through tears, Mr Carson’s mother, Margaret Sheehan, stood and faced her son’s killers as she read her victim impact statement in court during their sentencings in March.

“The gods have no greater torment for a mother than to outlive her children, how true these words are,” Mrs Sheehan said.

She spoke of her son’s kind nature, how he had once given her a shoebox with two pounds of sugar and a lemon.

“There was a sugar strike on in England at the time and I only drink lemon tea,” she said.

She said she would always remember his smile, his “cheeky grin”, and would miss his sense of humour and love of life.

“He always called me mother – sometimes mum, but mostly mother,” she said.

Mrs Sheehan said speaking of the death of her son was the most difficult thing she’d ever had to do.

Mark Carson's mother Margaret and stepfather David Sheehan, speaking outside the Maryborough courthouse, said he had been very well thought of in the Pacific Haven community.

“You are in my breaking heart, until we meet again.”

Her husband, Mr Carson’s stepfather David Sheehan, then read his victim impact statement to the court.

He spoke of Mr Carson’s “constant humour”, which was “such fun”.

Mr Sheehan said time had not eased the pain of losing his stepson.

While life should be relaxed and content, that was not possible because of his loss, he said.

“We will instead be haunted by an event which should never have happened. We have a life sentence,” he said.

He said Mr Carson would always continue to be part of their lives.

Mr Carson’s brother Chris then read out his statement.

He said the loss of his brother had impacted his whole family.

He’d had nightmares because of what he had to live with, because he couldn’t help or save his brother.

He said there were only two people responsible, naming the defendants.

“Your names will never be mentioned after today because my brother, Mark Carson, deserves to be remembered as the loving, kind, gentle-hearted man that he was,” he said.