An indictment filed in U.S. District Court in Portland charging two Nigerian men with the theft of 10.88 bitcoins worth about $59,000 from the US investors in just over six months.

According to the news release published by the Department of Justice, the defendants, Ogor Gift and Kelvin Usifoh, were charged with one count of conspiracy to commit wire fraud and one count of money laundering and 11 counts of wire fraud.

The defendants were accused of publishing various webpages to promise investors 20 to 50 percent returns on investments of bitcoin with zero risk and instant withdrawals. They actively encouraged victims to transfer bitcoin to private wallets and falsely claimed that their bitcoins would be invested using “unique trading methods” for  constant high interest rate.

Gift and Usifoh allegedly transfer the bitcoin to other accounts and eventually exchange it for Nigerian Naira. The defendants reportedly conspired to defraud three victims from Oregon and California.

The government alleges Gift and Usifoh received more than 50 bitcoins as part of the scheme. The case was investigated by the FBI and is being prosecuted by Quinn P. Harrington, Assistant U.S. Attorney for the District of Oregon.

As reported earlier this month, the US authorities have arrested a criminal group and charged them with drugs dealing and laundering millions worth of Bitcoin.