A jury has found former Toronto traffic officer Richard Wills guilty of first-degree murder in the slaying of his long-time mistress, Linda Mariani.

The six-man, six-woman jury returned the verdict after about 12 hours of deliberations in a Newmarket, Ont. courthouse.

"I suspect any judge sitting in your place would have returned the same verdict,'' Ontario Superior Court Judge Michelle Fuerst told the jury.

Following the verdict, Wills' teenaged daughter Jessica left the courtroom in tears and sobbed uncontrollably outside, calling out, "Daddy, Daddy.''

The conviction brought relief to the victim's family, who has endured Wills' antics for 5 1/2 years as the case dragged through the system.

"My heart was going about 200 miles an hour," Mariani's husband Dominic told reporters. "I wasn't 100 per cent sure (he would be convicted), but as soon as he stood up, it changed."

John Valeri, Mariani's brother, commended the jury.

"We're glad that the jury was able to see through the web of lies that Wills and the defence put forward," he said.

The outcome made veteran prosecutor Harold Dale well up when speaking to the media.

"I don't have to tell you that justice was done. It took a long time, but it was worth it," he said.

York police Det. Tim Gore added, "After this number of years that we've all had to endure this, finally it can come to an end."

Wills, 50, had pleaded not guilty to first-degree murder in the February 2002 death of Mariani. He was given a life sentence with no chance of parole for at least 25 years.

The 40-year-old mother's body wasn't found until Wills led police to it four months after she disappeared. Detectives found the corpse stuffed in a garbage bin located behind a fake wall in Wills' basement.

The Crown maintained Wills was a possessive lover who became enraged when Mariani wouldn't leave her husband.

Prosecutors alleged Wills struck Mariani with a baseball bat while inside his Richmond Hill home, then choked her with a skipping rope before sealing up her body.

During the sensational six-month trial, which included repeated outbursts by Wills, the former constable said Mariani's death was an accident. He maintained she fell down the basement stairs and struck the back of her head on the ceramic tile floor, and died almost instantly.

Wills testified he hid Mariani's body out of a sense of panic. He said he was worried Mariani's relatives would want to bury her in the family plot and not at his Wasaga Beach cottage property, where the couple had planned to be interred together under a secret lovers' pact.

After Wednesday's verdict, Wills told his lawyer Raj Napal "I'm innocent," and instructed him to file an appeal.

Shocking details

After jurors began deliberating on Tuesday, stunning information about the case they did not hear was allowed to be published, including the fact Wills offered to plead guilty to manslaughter at the outset in exchange for an eight-year prison sentence.

The ex-officer confessed to his best friend and Wills' ex-wife that he bludgeoned Mariani with a baseball bat and strangled her with a skipping rope. He also admitted the act to a psychiatrist in an unsuccessful bid to be found "not criminally responsible" by reason of a mental disorder. The psychiatrist said Wills knew exactly what he was doing, and diagnosed him with narcissistic personality disorder.

During the trial, Wills repeatedly interrupted proceedings and witness testimony by speaking out of turn. He swore aloud at his lawyers, court officials and even the judge. At one point, Wills defecated in his pants in a protest.

Another alarming detail that was allowed to be published on Tuesday was the fact the murder trial was expected to cost about $4 million -- half of that for Wills' legal fees, which will be covered by taxpayers.

Wills successfully convinced a judge he couldn't afford to hire lawyers, and an order was made that ordered the province to cover his legal fees.

Wills, however, became a millionaire early in his career through investments and co-owning a skating rink. But after being charged, he liquidated his assets and transferred control of his properties, his retirement funds and his monthly police pension to his estranged wife and three children. He then "pleaded poverty," CTV's Chris Eby reported.

The judge's order allowed him to receive funding for a lead counsel (who was paid $200 an hour) and junior counsel (who earned $140 an hour).

Wills has gone through 10 different defence lawyers (he fired most of them).

The Attorney General's office said late Tuesday that Wills' legal bills before his trial started cost taxpayers $804,000. After Wills' current lawyer is paid, that number is expected to climb to $2 million. Another $2 million has been spent on special court costs, including security.

After the verdict, Mariani's family urged Ontario's new attorney general, Chris Bentley, to investigate how Wills managed to drag out and nearly sabotage the trial and receive public funding for his legal costs.

With a report from CTV's Chris Eby and files from The Canadian Press