"A reminder that the media doesn't select the President," Murtaugh wrote.
But the newspaper front page which he shared - and which had been plastered on the walls of Team Trump HQ - was itself fake news.
In a spectacular own goal for the Trump team, Murtaugh hurriedly deleted the tweet - but not before the damage had been done.
The Washington Times shared Murtaugh's now-deleted tweet, correcting the record.
"Those photos have been doctored," it wrote on Twitter. "The Washington Times never ran a 'President Gore' headline.
"We also wish to add that Mr Murtaugh has been officially notified via email about this error."
The pile-on was immediate.
Trump himself continued his attack on the media this morning, tweeting: "Since when does the Lamestream Media call who our next president will be? We have all learned a lot in the last two weeks!"
He also continues to refuse to concede defeat to President-Elect Joe Biden, who was declared the winner on Sunday.
"I WON THIS ELECTION, BY A LOT," he tweeted yesterday in all caps.
Trump tweeted quotes from guests on Fox News morning programmes to bolster his baseless claims that the election result was fraudulent.
"We believe these people are thieves. The big city machines are corrupt. This was a stolen election. Best pollster in Britain wrote this morning that this clearly was a stolen election, that it's impossible to imagine that Biden outran Obama in some of these states," former Republican politician Newt Gingrich said, in one statement repeated approvingly by the President.
