Elizabeth Weise

USATODAY

SAN FRANCISCO — The federal government plans to auction $18 million worth of virtual money for cold, hard cash later this month.

The 29,000 virtual bitcoins to be auctioned were seized from the Silk Road website last fall. The anonymous website was a major sales point for illegal drugs and other underground goods.

The U.S. Marshals Service posted an announcement of the auction on Thursday.

Bitcoins are an unregulated online currency that are not backed by gold, silver or any other commodity.

Because they do not generally exist in the real world, what is actually being auctioned are sets of numbers that have been entered in an online public ledger. The sale will take place on June 27.

The bitcoins are to be auctioned off in blocks of 3,000, each worth about $1.8 million. The auction will take place over a 12-hour period.

Still under dispute are another 144,000 bitcoins that were owned by Ross Ulbricht, 30, the man behind Silk Road.

Federal agents arrested Ulbricht on Oct. 1 in the science fiction section of the Glen Park branch of the San Francisco Public Library.

He was charged with drug trafficking, money laundering and computer hacking, and is being held without bail in New York. He is charged separately in Maryland in connection with a murder-for-hire plot.

Ulbricht has pleaded not guilty.

The Silk Road website had nearly 1 million customers and $1.2 billion in sales, according to court papers in the case. Ulbricht allegedly collected commissions worth $80 million.