New York (CNN Business) A lawyer representing Lt. Col. Alexander Vindman, the National Security Council's Ukraine expert who testified publicly this week in the impeachment hearings, sent a letter to Fox News on Wednesday asking the network for a retraction.

The request for a retraction centers around an October 28 segment on Laura Ingraham's prime time show, "The Ingraham Angle."

During that segment , Ingraham seemed to suggest Vindman, a decorated military officer, was perhaps more loyal to Ukraine than the United States. Vindman was born in Ukraine but grew up in the US.

"Isn't that kind of an interesting angle on this story?" Ingraham asked her guest John Yoo, a law professor who served in President George W. Bush's administration.

"I find that astounding," Yoo replied. "Some people might call that espionage."

Read More