Paul Erickson was indicted in his home state of South Dakota on 11 counts of money laundering and wire fraud.
Natalia Veselnitskaya is accused of obstructing justice in a New York-based money laundering investigation that ended in 2017.
Mueller filed a previous indictment against them last October.
The four men had been jailed on drug and fraud charges.
Wilbur Ross's role as vice-chairman of the Bank of Cyprus has also drawn scrutiny.
Online giveaway of bitcoins prompts speculation of elaborate money laundering scheme.
The U.S. has declared the country a "primary money laundering concern."
Foreign companies will have to make their U.K. property portfolios public.
At least three people have been arrested as part of a larger investigation.
The scandal has gripped Russians online, but state media have remained quiet.