It's impossible to speculate what kind of potential financial crimes jettisoned McEntee from the White House, but they must be pretty serious if the Department of Homeland Security is running point on the investigation.
"It's not going to be great for morale", a White House official told The Journal about McEntee's firing.
McEntee was sacked and escorted out of the White House Monday, CNN reported, due to difficulties obtaining a permanent security clearance, an issue that has led to the departure of several White House staffers.
Trump and his wife, Melania, treated McEntee like a son, two people familiar with their relationship said.
The announcement came on the same day Mr Trump fired his secretary of state. CNN added more specifically that McEntee is "currently under investigation by the Department of Homeland Security for serious financial crimes". He looks to have already landed on his feet - just minutes after news of his departure broke, it was announced that McEntee would be joining Trump's reelection team as a senior adviser.
China advises US-North Korea to initiate denuclearisation talks
Wang ended his remarks with a warning: while the light is visible at the end of the tunnel, the road ahead will not be smooth. Visiting China in January, French President Emmanuel Macron said Belt and Road could not be "one-way".
McEntee was escorted from the White House on Monday.
McEntee, though, will continue to work for Trump.
McEntee declined a CNN request to comment.
For Trump, the absence of McEntee strips away another of the handful of close associates who have constantly been by his side as he made the transition from real estate mogul to politician. "John to promote the President's growing portfolio of achievements across the country". The cause of the firing was an unspecified security issue, said a third White House official with knowledge of the situation.