The U.S. government plans to auction over 2,700 bitcoins that were forfeited during several cases, several of which stemmed from investigations of the online black market. The U.S. Marshals Service on Monday said that the online auction would be held on Aug. 22, and that potential bidders must register by Aug. 18. The bitcoin are worth about $1.6 million, according to the Bitstamp exchange.

The auction is the latest by the Marshals Service of the digital currency.

The bulk of the bitcoins in the auction, 1,294, came from a civil forfeiture case related to a Silk Road (online black market) drug dealer, Matthew Gillum, who was sentenced in 2015 to nine years in prison, the Marshals Service said.

The agency said another 664 bitcoins came from the case of Sean Roberson, a Florida man who prosecutors said created an online shop for selling counterfeit credit and debit cards.