Lt. Col. Alexander Vindman arrives at the US Capitol on Nov. 7 in Washington, DC. Mark Wilson/Getty Images

Lt. Col. Alexander Vindman, the National Security Council's top Ukraine expert who testified last week before House impeachment investigators, was on Capitol Hill for more than 10 hours today to review his previous testimony.

About last week's testimony: For more than 10 hours, Vindman testified that he reported concerns about President Trump's July 25 call with the leader of Ukraine to the top National Security Council lawyer within hours, and said some of the changes he tried to make to the since-published transcript were left out, though he didn't say why. Later, he was told not to discuss the call with anyone else.

Despite testimony that will likely only fuel further inquiry, Vindman has been seen at work in the building next door to the White House. His return, multiple sources say, has been a mixture of business as usual with a pervasive sense of tension among staffers who are hoping to stay above the political fray that has consumed the typically inconspicuous council.

Vindman has no intention of leaving his post at the NSC, officials familiar with the matter said. Vindman, an Army officer who is currently detailed to the NSC, is expected to stay on in his role until his time is finished next summer, people around him believe, despite the recent spotlight he's found himself in.