Conversation so far:
What was the accusation?
looked extensively into the problem of unauthorized and uncontrolled powers exercised by non-elected officials, specifically White.
Was the accusations found to be valid?
Attorney General Herbert Brownell Jr.
revealed that the FBI had warned the Truman administration about White before the President appointed him to the IMF.
Why did they warn them?
revealed that the White House had received the FBI report on "Soviet Espionage in the United States," including the White case.

Question: Did they take the warnings seriously?
Self-contained rewrite: Did Truman administration take the warnings seriously?