Any professional poker player will tell you that winning poker requires you learn to bluff.

Poker legend Doyle Brunson, who we often see on TV in poker tournament finals, has certainly mastered the art of bluffing. But the problem, some investors say, is he took that skill to Wall Street in what appears to be a major rip-off.

Some angry complaints have already been lodged with the Securities and Exchange Commission, which, I’m told by a Nasdaq investigator, has kicked off an investigation into what a number of Wall Street pros believe was a bogus takeover offer for WPT Enterprises, the Hollywood, Calif., creator of the widely watched World Poker Tour telecast on the Travel Channel.

“You’ve heard of the week that never was,” the Nasdaq investigator said. “This looks like the deal that never was, and it has all the earmarks of stock manipulation.”

WPT, which is traded on Nasdaq, went public last August at $8. Thanks to burgeoning poker interest from a swelling population of more than 50 million American poker players, the stock subsequently more than tripled.

This month, though, the stock has been on a roller coaster, following a July 7 buyout offer of $700 million (equivalent to about $36 a share) from a group of investors led by Mr. Brunson. Not unexpectedly, when the offer was made public the next day, WPT’s shares – which had closed the day before at $17.75 – rocketed more than 60% to a new high of $29.50 and closed the session at $26.50, up $8.75. A shocker to many observers was the size of the offer, since it represented an abnormally high 100% premium over the prior’s day close (then a market value of around $357 million).

As it turns out, the bid by the Brunson group has suddenly turned into a no-bid, which, in turn, has caused WPT’s shares to tumble. They’re currently trading at $21.45, more than a 30% decline from their recent high.

Strangely, details of the proposed offer – which carried with it a deadline this past Tuesday at 5:15 p.m. – were never provided to WPT by the Las Vegas-based law firm, Goodman and Chesnoff, which originally presented the bid. Not only that, the law firm, prior to the deadline, issued a statement saying it no longer represented any of the parties involved in the offer. And that’s all it would say. When I rang up the firm seeking an explanation, a nervous spokesperson told me: “This is not something we’re allowed to talk about.” What about Mr. Brunson? More strange doings. On Monday, he indicated to WPT that he would provide no further information about the offer, but he has never disavowed the bid. Why he’s so mum is a mystery. I tried reaching the 71-year-old poker player, who won the World Series of Poker in 1976 and 1977, but he’s in another such tournament and could not be reached for comment. “The whole thing looks like a fraud, like someone was trying to manipulate the stock,” said Dave Ehlers, chairman of Las Vegas Investment Advisors. “I don’t know how you can see it much differently than that.”

Meanwhile, there is a sizable short position in WPT. One short seller in the shares thinks it’s inevitable that any probe will reveal one or more of the following:

* The bid was never real and some investors knowing that profited by buying the stock in advance of the offer and possibly sold it short after the run-up in price.

* The bid was real, but for some reason it fell apart in midstream, and no one ever disclosed that fact. In the process, some investors, aware of what was going on, illegally capitalized on that information, perhaps on the long side, the short side, or both.

* Some investors, aware of everything going on, may have also made money in Lakes Entertainment, which holds a 62% stake in WPT. Lakes, which also has a sizable short position, experienced a recent roller-coaster ride, as well.