Image copyright Court exhibit Image caption Dellen Millard at his father's firm MillardAir

A former Canadian millionaire and twice-convicted murderer has been convicted of killing his father, whose death was initially ruled a suicide.

Dellen Millard wept when he heard the judge pronounce him guilty of murdering his father Wayne Millard.

Millard is already serving two life sentences for the murders of Laura Babcock and Tim Bosma.

He inherited the family fortune after his father was found shot in the head.

The 2012 death was originally ruled a suicide, but on Monday an Ontario Superior Court judge found him guilty of shooting his father while he slept.

Millard had told police his father had been depressed and an alcoholic.

"He carried some great sadness with him throughout life that I never knew - he never wanted to share that with me," he said the day after his father died.

But employees at MillardAir, the family's aviation company, said there had been tensions between Millard and his father, according to a CBC investigation.

Six months later, the disappearance of Tim Bosma set off a chain of investigations that would eventually lead to Millard being charged with three murders.

'It was just a truck'

The 32-year-old was trying to sell his vehicle when Millard responded to an ad online. Millard and his friend Mark Smich met Bosma at his family home outside Hamilton, Ontario.

Bosma agreed to go with the pair while they took it for a test drive in May 2013. He was never seen again.

"It was just a truck, a stupid truck," Bosma's wife said, before Smich and Millard's arrest.

Bosma's truck was eventually found by police on a property owned by Millard's mother, and soon he and Smich became prime suspects in his murder. The truck had been stripped, but gunshot residue and traces of his blood were found inside.

Police also began digging around into Millard's past, his father's death, and the disappearance of his former partner Laura Babcock the year before.

The first killing

Three months before his father's death, Babcock had gone missing.

Eventually, police would learn that she had been involved in a love triangle between Millard and his current girlfriend, and that Millard had promised to "remove her from our lives".

Her body was never found, but soon after her disappearance Millard purchased an incinerator. Police have never been able to identify Babcock's and Bosma's remains, but believe both were shot and their bodies burned.

Millard and Smich were found guilty of Bosma's murder in 2016; they were also found guilty of murdering Babcock in 2017.

Father and son

Police then began to re-examine Wayne Millard's apparent suicide following the convictions,

Prosecutors alleged Millard wanted to kill his father to protect his inheritance, which was being used to fund a new aviation business.

Millard said he was at Smich's house the night of his father's death, but phone records reveal he travelled back to his father's house in the early hours of the morning.

A gun purchased by Millard illegally was also found next to his father with Millard's DNA on it.

Smich was not charged in the death of Millard's father.