The U.S. Department of Justice has charged a 31-year-old former product manager at the NFT marketplace OpenSea with wire fraud and money laundering in connection with what appears to be the first case of NFT insider trading to hit the U.S. court system.

The court documents allege that Nathaniel Chastain was responsible for selecting which NFTs would be displayed on OpenSea’s homepage, and that he then used this insider information to make personal financial gains.

“NFTs might be new, but this type of criminal scheme is not. As alleged, Nathaniel Chastain betrayed OpenSea by using its confidential business information to make money for himself,” U.S. attorney Damian Williams said in a statement. “Today’s charges demonstrate the commitment of this office to stamping out insider trading—whether it occurs on the stock market or the blockchain.”

In Manhattan court on Wednesday, Chastain pleaded not guilty to the charges, each of which carries a maximum 20-year prison sentence.

He is accused of buying 45 digital assets before they were featured on the website on 11 different occasions between June and September of 2021. Chastain then flipped works, such as Spectrum of a Ramenfication Theory by Dailydust, for profits of two to five times the purchase price.

Chastain is believed to have used anonymous digital currency wallets and anonymous accounts on OpenSea to conceal his identity in the sales.

“When all the facts are known, we are confident he will be exonerated,” David Miller, Chastain’s lawyer, told Reuters.

The apparent scheme was uncovered in September. A Twitter user pointed out that the transaction receipts and Ethereum addresses for sales of featured NFTs could be linked back to Chastain because of his public ownership of CryptoPunk #3501, currently valued at 26.98 ETH ($48,387). (Decentralized finance asset management platform Zapper currently puts Chastain’s total wallet assets at $281,726.)

At the time, the crypto news service 8BTC estimated that Chastain had made 19ETH ($67,000) in the trades.

When the allegations against him first surfaced, Chastain resigned from his position at OpenSea at the request of the company.

“This is incredibly disappointing. We want to be clear that this behavior does not represent our values as a team,” OpenSea co-founder and CEO Devin Finzer wrote in a statement at the time.

OpenSea has since instituted new policies prohibiting employees from buying or selling work by creators while the company is featuring or promoting them, or from using any insider information for NFT transactions on any platform.

“When we learned of Nate [Chastain]’s behavior, we initiated an investigation and ultimately asked him to leave the company,” OpenSea said in a statement. “His behavior was in violation of our employee policies and in direct conflict with our core values and principles.”

Prior to the indictment, Chastain was seeking investors for a new NFT platform called Oval that would use recommendation algorithms to personalize the NFT collecting experience, according to CoinDesk.

It remains to be seen whether the government crackdown on manipulated NFT sales will extend more broadly to the cryptocurrency market, where sellers routinely “washtrade,” or purchase their own assets to make them appear more valuable and encourage other investors to buy in.

“Trading against your own customers is absolutely standard in crypto,” read an analysis on the cryptocurrency news site Attack of the 50 Foot Blockchain. “Chastain’s mistake was that he assumed OpenSea worked like a crypto exchange—where he could insider-trade, and nobody would care.”

Though Chastain is the first to be charged with NFT insider trading, it’s likely he will not be the last.

“With the emergence of any new investment tool, such as blockchain supported non-fungible tokens, there are those who will exploit vulnerabilities for their own gain,” FBI assistant director-in-charge Michael J. Driscoll said in a statement. “The FBI will continue to aggressively pursue actors who choose to manipulate the market in this way.”