MANDEL: Pickering husband, hit man he hired to kill wife lose murder appeal

David Knight, Graham MacDonald were convicted in 2018 of 1st-degree murder of Carmela Knight

Published Jun 24, 2026  •  4 minute read

Carmela Knight, 39, was found dead inside her burnt-out garage in Pickering, Ont. Photo by Toronto Sun files

The Pickering husband and the hit man thought they could get away with killing his wife.

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But in 2018, a judge convicted David Knight and Graham MacDonald of first-degree murder in the death of mom Carmela Knight, 39, after the hired assassin unwittingly confessed the plot to “friends” who were actually police officers involved in a three-month undercover sting operation.

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On appeal, they claimed MacDonald’s “Mr. Big” confessions were an abuse of process and should have been inadmissible. Ontario’s highest court has just disagreed.

In 2014, Carmela, the mother of two, had discovered her husband was having an affair and demanded a divorce along with child and spousal support. She had just filed an emergency family court motion for sole possession of the marital home that was to be heard in three days. Court heard Knight’s answer was to hire MacDonald to strangle her to death, drag her body into the garage, douse her with gasoline and set her on fire.

Court heard he would then be able to be with his Florida mistress and collect on his wife’s $850,000 life insurance plan — cash he needed to close on his purchase of a Florida construction business.

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Carmela Knight, 39, was found dead inside her burnt-out garage in Pickering, Ont. Photo by CHRIS DOUCETTE /TORONTO SUN

Body found in burnt-out garage

On Sept. 15, 2014, firefighters put out the blaze in the family’s Pickering garage on Pebblestone Cres. and discovered Carmela’s charred body: She’d suffered blunt-force injuries to her face and had died of strangulation. Court also heard the scene had been staged to make her death look like a suicide — a tourniquet was wrapped around her arm, a syringe was found nearby and someone had unsuccessfully tried to inject cocaine into Carmela’s arm.

Knight was an obvious suspect, but he was at hockey practice at the time with the couple’s two sons. Acting on a tip, Durham Regional Police learned MacDonald, a handyman with an extensive criminal record, was Knight’s friend and may have done some work at the family home.

They targeted MacDonald in an elaborate “Mr. Big” operation — a controversial Canadian police technique where undercover officers create a fictitious criminal organization to befriend a suspect and elicit a confession.

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Court heard that MacDonald met “Rob” at the Port Hope motel where he was staying and over the course of three months they became good friends as MacDonald helped Rob in fictitious sales of stolen property. Rob then introduced MacDonald to his mentor “Uncle Dan,” who had previously helped him get out of trouble with the law.

He, of course, was unaware that both men were undercover officers recording his every word.

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Murder plot discussed for months

Court heard MacDonald needed help — he confessed to Rob and Uncle Dan that he’d killed Carmela in exchange for $100,000 and a job in Florida, but Knight had only paid him $2,000 and then disappeared. Uncle Dan offered to get his dying friend “James” to confess to the murder in return for $20,000 to be paid to his surviving kids, but he’d need all the details to make it convincing — which MacDonald provided to a third cop posing as a man with terminal cancer.

He boasted to his new friends that he and Knight had discussed the murder plot for months, court heard, and had planned to spike her morning smoothie until the suspicious Carmela stopped drinking them.

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On the day of the murder, he said Knight drove him to his house and he hid in the basement until Knight left with his kids to hockey practice. MacDonald said he then waited until Carmela came home and after a heated struggle, court heard he choked her to death with a ratchet strap, staged the scene in the garage, planted cocaine in her purse, set her body on fire and fled, narrowly escaping the blaze.

The hit man’s confessions, recorded by the undercover officers, guaranteed his conviction at his judge-alone trial. At Knight’s trial before a judge and jury, MacDonald refused to testify, but the judge found enough independent evidence to allow the jury to hear the police recordings.

Knight, too, was convicted and both killers were sentenced to an automatic life sentence with no chance of parole for 25 years.

The Court of Appeal found no errors were made by either judge at the men’s trials, so they will remain where they belong.

“He was supposed to love and protect Carm, not murder her,” Carmela’s grieving mother Franca Agosta was quoted as saying by durhamregion.com at Knight’s sentencing hearing in 2019. “He had no mercy for Carmela and the court should have no mercy for him.”

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