Every gambler knows that for a run of good luck, there's an equal string of bad lying in wait. The trick is walking away while the going's good.

On Tuesday afternoon, the going was great for Harnam Matharu at the Fallsview Poker Classic at the Fallsview Casino in Niagara Falls, Ont. He slapped down a $1,100 buy-in and proceeded on the best run of his recorded poker career.

The Fallsview tournament is not for chumps. With a $5-million purse, it attracts some of the best players in the game.

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Mr. Matharu is not considered one of them.

With career earnings of about $7,000, he ranks somewhere south of 100,000th in the world standings, according to the Global Poker Index.

He showed no sign of meagre talent at Fallsview. The affable 21-year-old made his way through a series of preliminary games – surpassing more than 600 other players – all the way to the final table. The grand prize: $200,000.

"You sometimes wait your whole life for an opportunity like that," said Brian Friesen, an avid player from Winnipeg who watched the final game.

"It's a big tournament and hard to win."

But as the day wore on, a few veteran players thought they recognized Mr. Matharu from a recent tournament in Kahnawake, Que., where one player was attacked outside a Châteauguay motel room and robbed of $5,000.

The Nov. 25 assault was caught on motel cameras, but the suspect fled town and police issued a Canada-wide warrant for his arrest.

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The Manitoba contingent decided to investigate further. One of them took a cellphone picture of Mr. Matharu and e-mailed it to the robbery victim, Uri Miro, who confirmed it looked like his attacker, according to Mr. Friesen, and forwarded the tip to investigators in Châteauguay.

Meanwhile, Mr. Matharu was sustaining his career day.

By the time the game broke for dinner, around 6:45 p.m., he was the chip leader, well on his way to a legitimate $200,000 payday.

That's when the Ontario Provincial Police's Casino Enforcement Unit took over.

"Two big, burly officers moved in and escorted Matharu outside in handcuffs," said Mr. Friesen. "The whole thing went down very quietly. He was very passive and submissive."

The OPP acknowledge the arrest didn't come at the most opportune moment for Mr. Matharu.

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"This wasn't overdue parking tickets; this was a Canada-wide warrant on very serious charges with a police service willing to travel from another province to return him," Casino Enforcement Unit member Detective Sergeant Rick Davidson said.

"The player's position or stake in the poker game, as unfortunate as that may or may not have been, becomes nearly irrelevant when I apply the public-safety test. And that is my primary concern."

A Châteauguay investigator interviewed Mr. Matharu on Thursday, said Nadia Grondin, a spokeswoman for the force. He'll appear before a court on Friday.

While Mr. Matharu's personal fortunes went bust, his table luck did not.

When the remaining players returned to the game, they were surprised to see his seat vacant. As per tournament rules, they maintained his hand in absentia, keeping tabs on his antes and blinds.

Two players ran out of chips before a winner was finally declared, leaving Mr. Matharu with a third-place take of $80,000.

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"The poker crowd isn't always the most savoury of characters," Mr. Friesen said.

"But this shows you have some safety in a casino. The fraternity of poker players found him, caught him and turned him in. If he stays in the game and wins $200,000, you'll probably never see this guy again."