A high-profile prosecution involving a $10 million Markham mansion that was reportedly used as a high-end illegal casino is in disarray, with police officers allegedly stealing valuables and planted evidence.

Last year, York Regional Police launched “Project Endgame,” an investigation that unearthed a series of underground casinos. The busts were revealed at the end of last summer with a glossy police video showing officers raiding a lavish mansion in Markham, Ont., north of Toronto, and taking away baccarat tables.

According to York police, 32 people were arrested and 11 firearms, nearly $1 million in cash, and the mansion itself were seized. Wei Wei, the 53-year-old homeowner, was one of those charged. His adult daughter and wife were both accused of running a gaming/betting house.

However, when the Crown dropped charges against the Wei family this spring, including claims that Mr. Wei had illegally kept guns, there was no publicity. Meanwhile, Mr. Wei decided to give up his claim to all of the seized assets, including $960,000 in cash and half of the seized multimillion-dollar house (though his wife will keep her share).

Mr. Wei and his lawyer, Danielle Robitaille, had been complaining for months about valuables that reportedly went missing during the raid.

A letter dated May 15 that Ms. Robitaille sent to Ontario’s Office of the Independent Police Review Director reads that “In the course of our work defending Mr. Wei we uncovered troubling evidence pointing to evidence of serious police misconduct.”

Her letter claims that a close examination of police-disclosed photos and videos taken over a two-day period following the raid reveals things going missing and things occurring where they weren’t supposed to be.

She writes that “Members of the YRP (York Regional Police) appear to have stolen two watches belonging to Mr. Wei valued at approximately $450,000.”

She also alleges that police “have planted evidence, namely a gun holster, in a room associated with Mr. Wei while executing the same warrant.”

These charges have not been proved in court, and police and prosecutors are refusing to comment. Since March, when prosecutors separately informed the force of the problems, they have been the subject of a police internal-affairs investigation.

But Ms. Robitaille told the OIPRD she wants the outside agency to investigate.

She said that “Given the way YRP made a significant public spectacle of the results of their investigation into Project Endgame … we have grave concerns that the internal investigation into this troubling misconduct will fail to adequately probe the case.”

York Regional Police said in an emailed statement that they are conducting a thorough investigation into Mr. Wei’s lawyer’s complaint.

The force’s statement also emphasized that the overall case has not collapsed. Multiple accused are still before the courts awaiting resolution to their charges or trial.  Wei Dong, for instance, is also facing firearms and gaming/betting house charges. Calvin Barry, his lawyer, said in an interview that he would challenge the charges based on Wei Wei’s allegations.

Four other people arrested during the bust, according to a spokesperson for the Ministry of the Attorney-General, are also in court.

When the charges against Wei Wei were dismissed, he entered a court-enforced agreement to keep the peace and stay away from casinos, as well as surrendering his share of the Markham property, according to the York Regional Police statement.

York Constable Laura Nicolle said in an e-mailed statement that “Overall, we are content with this outcome.”

The home is currently for sale for $9,980,000. It’s described as a 30,000-square-foot property with chandeliers, an elevator, three dining rooms, an indoor swimming pool, and a spa in a real estate listing.

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