WASHINGTON, D.C. — A pentagon official who raised concerns about a controversial hold on Ukraine military aid is stepping down.

Elaine McCusker was sworn in as Deputy Under Secretary of Defense (Comptroller) on August 7, 2017.

Defense Secretary Mark Esper said Tuesday that she submitted her resignation and will leave later this month.

McCusker has questioned the legality of the White House decision to put on hold nearly $400 million in aid to Ukraine last year.

That issue eventually led to President Trump’s impeachment in the House of Representative, before he was acquitted after a trial in the Senate.

There’s still no word on why McCusker is leaving.

But her resignation came three months after the White House pulled her nomination to be the Pentagon’s comptroller.

CNN Newsource contributed to this article.