President Donald Trump meeting with Russia's American ambassador Sergei Kislyak and Foreign Minister Sergey Lavrov (via Creative Commons).

Robert Mueller has added a former U.S. Supreme Court clerk who speaks Russian to his team investigating the Trump campaign’s possible ties to the Kremlin.

Elizabeth Prelogar, an assistant to the solicitor general, is assisting deputy solicitor general Michael Dreeben in his part-time role on the special counsel’s team probing the Trump campaign, reported The National Law Journal.

Dreeben is considered the Justice Department’s top criminal law expert, according to the publication, and his participation is seen as a sign that Mueller is investigating possible criminal violations by President Donald Trump or his associates.

Prelogar served as a law clerk to Justices Ruth Bader Ginsburg and Elena Kagan, and she appears to speak fluent Russian, which she studied at Emory College.

She graduated from Harvard Law School in 2006 and was previously a Fulbright scholar in Russia, and she also won an Overseas Press Club scholarship to study Russian media and censorship.