U.S. Special Counsel Robert Mueller on Tuesday stepped up pressure on two former Trump campaign aides to cooperate in his probe into possible collusion with Russia, unsealing a criminal charge against a lawyer for lying to Mueller's investigators.
The attorney, Alex van der Zwaan, the son-in-law of one of Russia's richest men, pleaded guilty in U.S. District Court in Washington, D.C., to a charge of lying to the Special Counsel's office. A U.S. judge set his sentencing for April 3.
The case involves work that van der Zwaan, a 33-year-old Dutch citizen, performed in 2012 about Ukraine for Paul Manafort and Rick Gates, senior officials in Donald Trump's 2016 election campaign.
The two former aides have been charged with conspiracy to launder money and failure to register as foreign agents in connection with work for a pro-Russia Ukrainian party.
The charge against van der Zwaan makes no reference to Trump's campaign or the 2016 election.
But legal experts said the charge would put more pressure on the former Trump aides to cooperate with Mueller as he looks into whether Russia tried to influence the election in favor of Trump by hacking the emails of leading Democrats and distributing disinformation and propaganda online.
Last year, U.S. intelligence agencies found that Russia had meddled in the election and that its goals eventually included aiding Trump who won a surprise victory over Democrat Hillary Clinton.
The lawyer's case appears to underscore the extent of Mueller's probe and of his interpretation of how far and wide he can investigate.
Manafort, who was Trump's campaign manager for almost five months in 2016, and Gates, who was deputy campaign manager, pleaded not guilty last year to Mueller's charges.
Lawyer van der Zwaan's father-in-law is Russian billionaire German Khan, the founder of the privately-owned Alfa Bank.
Even if van der Zwaan "is only cooperating against Paul Manafort, that could be very valuable in the big picture. Prosecutors typically very methodically start with low-level offenders and try to work their way up the chain," said Barbara McQuade, a former U.S. attorney for the Eastern District of Michigan. "My guess is he is cooperating."