Regulators have cracked down on an alleged Ponzi scheme involving the virtual currency bitcoin as they issue a more general warning about the dangers of such scams for investors.

A Texas man, Trendon T. Shavers, was sued by the Securities and Exchange Commission on Tuesday and accused of running a fund that collected bitcoins from investors, promising them 7 percent weekly returns. Mr. Shaver ended up selling some of the bitcoins and using the proceeds for his “rent, car-related expenses, utilities, retail purchases, casinos, and meals,” according to the complaint.

Related Links The S.E.C. complaint

Investors have been willing to pay significant real money for bitcoin since the currency was created by anonymous computer programmers in 2009. As the value of the digital coins has skyrocketed, so has attention from regulators around the world, who have worried about the potential for fraud and money laundering.

In an investor alert released Tuesday, the S.E.C. warned, “We are concerned that the rising use of virtual currencies in the global marketplace may entice fraudsters to lure investors into Ponzi and other schemes in which these currencies are used to facilitate fraudulent, or simply fabricated, investments or transactions.”

In the complaint, the agency said that Mr. Shavers, using the online name “pirateat40,” began advertising the Bitcoin Savings and Trust in 2011 on online forums in 2011. Mr. Shavers promised to make money trading the coins online and deliver the profits to his investors. He ended up collecting more than 700,000 bitcoins, according to the complaint. Those would have been worth about $4.5 million using the conversion rate in 2012, and more than $65 million at today’s rate.

The S.E.C. is asking a federal court in Texas to freeze Mr. Shaver’s assets while the case moves ahead.

Mr. Shaver could not be reached for a comment.