On the heels of regulators red-flagging a potential $18 million scam last week, multiple federal agencies are probing investments sold to NFL and NBA players, Yahoo! Sports has learned.

According to multiple sources that spoke to Yahoo! Sports on the condition of anonymity, several professional athletes have either been contacted or been urged to contact investigators from the U.S. Department of Justice, the FBI and the U.S. Securities and Exchange Commission.

Three sources also told Yahoo! Sports that the NFL Players Association has asked a handful of its athletes with investments tied to Jade Management to contact FBI investigators. Jade previously managed finances for dozens of professional athletes, and had investment ties to Success Trade – a firm that came under fire from the Financial Industry Regulatory Authority (FINRA) last week. Success Trade was ordered to halt fundraising last week after allegedly selling $18 million in fraudulent and unregistered promissory notes to 58 persons, many of whom were NFL and NBA players.

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Jade Management founder Jinesh "Hodge" Brahmbhatt told Yahoo! Sports his firm had more than 30 athletes who purchased high interest investments that FINRA now says were fraudulent. Some of those investments purportedly generated interest returns between 11 and 26 percent.

In a complaint filed by FINRA and obtained by Yahoo! Sports, regulators allege that multiple athletes involved with Success Trade were introduced to the fraudulent notes by representatives of Jade Management. Success Trade is alleged to have made at least $1.25 million in payments to Jade Management since March 2009.

During an 18-month investigation, Yahoo! Sports identified multiple athletes that purchased promissory notes from Success Trade. Among them were Detroit Pistons guard Brandon Knight, Cleveland Browns cornerback Joe Haden, San Francisco 49ers tight end Vernon Davis, former Washington Redskins running back Clinton Portis and former Chicago Bears defensive end Adewale Ogunleye.

Brahmbhatt told Yahoo! Sports late last week that he had more than 30 clients who had purchased around $12 million worth of the fraudulent notes from Success Trade. Sources said those investments ranged anywhere from $50,000 to more than $500,000.

Late last week, Brahmbhatt sent an email to some of those clients indicating he was unsure whether they will get their money back.

"We have told [Success Trade CEO Fuad Ahmed] that what is most important is getting you paid back," Brahmbhatt said in his email to athletes. "We believe that this is what he is trying to do. It is not clear whether he will be able to accomplish this, given the FINRA action and a number of other hurdles."

Brahmbhatt said that while a number of his clients were involved with Success Trade deals, he maintained his company did not improperly benefit from those deals.

"I just hope nobody says, 'the guys at Jade capitalized on this,' " Brahmbhatt said. "Because we never did. Other than the first year we took [$1.25 million] from him … everything we did for him is because we actually liked it."

Brahmbhatt contended that he had no reason to believe Success Trade was acting improperly while drawing investor money, but added that he didn't have full knowledge of the company's financial practices.

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"We don't have [Success Trade's] books," he said. "People say, 'Man, you're stupid. You should have looked at [Success Trade's] last two or three years of income statements.' But you know what? We didn't. You know why we didn't? Because he never missed a damn payment, and we never really thought about it."

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