An aviation executive whose death was initially ruled a suicide had been making plans to celebrate his girlfriend's birthday before he was found with a bullet lodged in his brain, a Toronto court heard Thursday.

Janet Campbell said she was shocked when Wayne Millard's son told her his father appeared to have killed himself days before her birthday.

Dellen Millard has pleaded not guilty to first-degree murder in his father's death. It's the third time the 32-year-old is standing trial for first-degree murder -- he's currently serving two consecutive life sentences for separate convictions.

Campbell said Wayne Millard, 71, was in love with her and the two would talk for hours on the phone, including the night before he was found dead. They made plans to talk the next day, but when Campbell couldn't reach him, she emailed his son, court heard.

"He said 'my father was dead and it would appear to be by his own hand,"' Campbell told the judge-alone trial. "I was stunned, totally and absolutely stunned."

Court documents have shown Dellen Millard was the one who found his father's body on Nov. 29, 2012 in the home the two shared in Toronto. The younger Millard called his mother, who came to the home and then called 911, documents show.

Campbell said she had reconnected with Wayne Millard, her cousin through adoption, in early 2012. The two had dated when they were teenagers, she said, but lost touch in the intervening 50 years. He reached out to her and they began a friendship that became romantic by November 2012.

The pair often discussed Millard's business -- Millardair -- which was in the midst of being revamped to become an aircraft maintenance and repair operation at a brand new, multi-million dollar hangar at the Region of Waterloo International Airport.

"Things were coming together at that point" for Millardair, Campbell said. The company had just secured a valuable license from Transport Canada on Nov. 1 to operate, court documents show.

Campbell said Millard would be stressed at times because of the business, but it didn't seem unmanageable.

"I wouldn't say a great deal of stress," she said under repeated questioning from Dellen Millard's lawyer, Ravin Pillay.

The lawyer portrayed the elder Millard as a recluse and an alcoholic, which Campbell agreed with, though she said he never drank when the two of them were together.

But she disagreed when Pillay said Wayne Millard suffered from depressed.

"I don't want to say he suffered from depression, he was depressed like everyone else," she said. "I don't think he was clinically depressed."

Campbell said Wayne Millard had booked Dec. 4 off for her birthday, and hinted at his gift for her.

"He said 'you're not going to like it at first, but will come to love it," Campbell said.

About two weeks after his death, when friends and family gathered at a restaurant north of Toronto to remember Wayne Millard, his son gave Campbell the gift his father had planned -- they were flying lessons, court heard.

It was the first time she met the younger Millard, Cambell said, noting she didn't remember much of their conversation.

"I said I would need a hug," she told court.

Dellen Millard, dressed in a grey blazer and blue jeans, smiled back at her from the prisoner's box.

His mother, Madeleine Burns, appeared briefly in court and was ordered to appear as a witness in a few weeks.

William Smith, the paramedic who responded to a call for a cardiac arrest, testified that Wayne Millard was cold to the touch when he entered the bedroom on the night of Nov. 29.

He said Dellen Millard told him that he "tried to get a hold of his father for a few days, came over to the house, found him dead in the bed and called us."

Det. Const. Jeffrey Johnston, a forensic officer with Toronto police, showed the court photographs of Wayne Millard's body.

They show him lying on his left side, his right arm tucked under cheek, left arm outstretched. There is blood on the left side of his face, his arms, the bed and pillow.

A revolver sits on top of a Lululemon bag on the floor beside the bed. One bullet was fired, Johnston testified, and five others remained in the .32-calibre Smith and Wesson.

Police re-opened the investigation into Wayne Millard's death after Dellen Millard was arrested for the murder of Hamilton man Tim Bosma. Investigators charged Millard in 2014 in his father's death.

Millard and his friend Mark Smich are serving life sentences for murdering Bosma and Toronto woman Laura Babcock, whose mother was in court on Thursday.