Dellen Millard has been found guilty of killing his father, Wayne Millard.

Justice Maureen Forestell handed down her decision in Ontario Superior Court in Toronto on Monday, saying Dellen Millard carried out a "planned and deliberate killing" of his father.

"I am satisfied beyond a reasonable doubt that Dellen Millard killed his father by shooting him in the left eye as he slept," the judge said.

Slumped over in the prisoner's box, Millard softly cried as the judge gave her decision. For much of the almost two-hour hearing, Forestell seemed to be siding with the defence on many issues, calling into question the reliability of some witness testimony and saying the crime scene where Wayne Millard's body was found had been disturbed by first responders.

Then toward the end of her 36-page decision, Forestell began talking about Millard's "false alibi" — that he spent the night his father died back in 2012 at the home of his friend, Mark Smich. That's when Millard's jaw dropped, and he stared at her from the prisoner's box, aghast.

The Millard family must live with the fact that this heinous individual murdered his own father. - Clayton Babcock , Laura Babcock's father

As he was led out of the courtroom in shackles, many people in the courtroom broke out into applause.

The Crown said it will be seeking a consecutive life sentence in the case. Sentencing is scheduled for Nov. 16.

Assistant Crown attorney Ken Lockhart told reporters outside the courthouse that the decision marks the end of a very long process.

"We're very grateful for the many people who put in a lot of time, effort and heartache into these prosecutions," he said.

Dellen Millard has been found guilty of killing his father, Wayne Millard. 8:15

The judge's decision caps off a winding journey through the courts for Millard, 33, who has already been convicted of two other first-degree murders — the deaths of Hamilton man Tim Bosma and Toronto woman Laura Babcock.

Babcock's father, Clayton, spoke outside the courthouse while flanked by his wife, Linda, and Bosma's parents, Hank and Mary.

"It's been proven that not only did the Bosmas and ourselves lose a loved one, the Millard family must live with the fact that this heinous individual murdered his own father," Babcock said.

Clayton Babcock, right, stands with his wife, Linda, outside the courthouse at 361 University Ave. in Toronto on Monday. Mary Bosma and her husband Hank, left, look on. (Paul Smith/CBC)

"For all those out there who believe that the sentence of an additional 25 years to Mr. Millard's 50 years is too harsh, we say you haven't dealt with this kind of sorrow. We live with a cloud of sadness and loss over us every day. Like all people who have lost a close loved one through tragedy, there'll be not a day in our lives where the loss of Laura, Tim or Wayne won't be felt."

Originally ruled a suicide

Millard's third trial was held in front of a judge alone, as Ontario's attorney general agreed that the Toronto man's previous high-profile trials would make it difficult to find fair jurors. Closing submissions marked the end of evidence at the three-week trial on June 22.

Wayne Millard's death was originally ruled a suicide. He was found at his home at 5 Maple Gate Crt. in the Toronto suburb of Etobicoke on Nov. 29, 2012, after he was shot in the eye. At the time, Dellen Millard was living at his father's home.

He wasn't charged in his father's death until 2014, after police started investigating the slayings of both Bosma, a husband and father from the Ancaster area of Hamilton, and Babcock, a Toronto woman who had been involved with Millard.

Millard is serving consecutive life sentences for those slayings.

A single bullet was found lodged in his father's brain. Dellen's DNA was on the gun. (Court exhibit)

Outside court, Det. Mike Carbone of the Toronto Police Service refused to answer questions about how the investigation unfolded at the outset, when police and the coroner originally determined Wayne Millard shot himself.

"I'm not going to comment on whether or not it would have prevented any other investigations, because we really don't know," he said.

Once the case was reopened, investigators discovered that Millard's DNA was on the gun used to shoot his father, and his cell phone had pinged off nearby cell towers around the time it's believed Wayne died.

Whether Wayne killed himself emerged as the trial's key question as the evidence unfolded.

The Crown argued that Dellen shot his father to escape a legacy and business being built for him that he didn't want, as his father was building an aviation business with family funds.

His defence team, meanwhile, discounted the Crown's motive in its own closing submissions.

"Not a single witness came before this court and suggested there was any discord between Mr. Millard and his father," said his lawyer, Ravin Pillay. "There is nothing in the record before you that supports this one way or another."

Pillay did not speak to reporters after the judge's decision. Millard is appealing his conviction in both the Bosma and Babcock murders.

Read a recap of CBC's live blog from inside the courtroom here. On mobile? View the blog here.

adam.carter@cbc.ca