One of the Department of Interior's (DOI) internal watchdog investigations into Interior Secretary Ryan Zinke's behavior while in office has been referred to the Justice Department, which only happens when investigators determine there might have been a criminal violation, The Washington Post reported Tuesday.

Two sources familiar with the investigation broke the news to the press, but did not specify which of the probes into Zinke's actions was involved. A senior White House official only told The Washington Post that the investigation revolved around whether Zinke "used his office to help himself."