Alex van der Zwaan arrives at a plea agreement hearing at the D.C. federal courthouse in Washington, U.S., February 20, 2018. REUTERS/Yuri Gripas

WASHINGTON (Reuters) - A lawyer and son-in-law of one of Russia’s richest men pleaded guilty on Tuesday to a charge of lying to federal investigators as part of U.S. Special Counsel Robert Mueller’s probe into Russia’s alleged interference in the 2016 U.S. presidential election.

Alex van der Zwaan, who appeared at a hearing at a federal court in Washington, will face sentencing on April 3.