(Bloomberg) -- US authorities are ratcheting up pressure on Sam Bankman-Fried’s inner circle as they scrutinize former close FTX associate Nishad Singh, according to people familiar with the matter.

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If federal prosecutors in Manhattan find Singh had a role in the alleged multiyear scheme at FTX and trading firm Alameda Research to defraud investors and clients, he could be charged as soon as this month, said one of the people. The Securities and Exchange Commission and the Commodity Futures Trading Commission are also probing Singh, said the person, who asked not to be identified discussing the matter.

The scrutiny of Singh, who until recently lived with Bankman-Fried in a Bahamas penthouse and was a high school friend of his younger brother, Gabe, presents the latest legal threat to Bankman-Fried as he fights a slew of criminal charges. Former close associates Caroline Ellison and Gary Wang have pleaded guilty to fraud in connection to their roles at Alameda and FTX and are working with authorities.

It’s unclear whether Singh, who hasn’t been accused of wrongdoing, is cooperating with US officials or will do so. Andrew D. Goldstein, a lawyer for Singh, declined to comment, as did representatives for the US Attorney’s Office for the Southern District of New York, SEC and CFTC. Goldstein previously served as the chief of SDNY’s public corruption unit, which is now part of a special FTX task force.

The ongoing, sprawling investigation into November’s spectacular collapse of FTX is one of the highest-profile corporate crime cases in US history. Prosecutors and regulators have alleged that Bankman-Fried orchestrated a years-long scam, which involved misleading investors and misusing billions of dollars of FTX customer funds to pay off debts and expenses of Alameda, the trading firm he also founded.