Pres. Donald Trump’s top legal advisers are scrambling to come up with evidence to back his claim on Twitter Saturday morning that the phones at Trump Tower were tapped in the weeks leading up to the 2016 election.

The New York Times reported Saturday evening that while Trump is spending the weekend at his Mar-a-Lago resort in Florida — his fourth weekend away from Washington since he was inaugurated Jan. 20 — a source reported that senior White House Donald F. McGahn II is spending the weekend trying to secure access to a court order that may or may not exist.

There are two possibilities regarding Trump’s angry tweets from Saturday morning in which he accused former Pres. Barack Obama of wiretapping the phones in Trump Tower: One is that Pres. Trump is getting his news from right-wing radio and fringe conspiracy websites like Breitbart.com and InfoWars, both of which ran with a story on Friday alleging that Obama eavesdropped on Trump.

The other possibility, as suggested by Democratic Rep. Ted Lieu (CA), is that the president was under surveillance through an order from a FISA court. This would mean that a federal judge felt there was probable cause to believe that Trump had committed a serious crime or was an agent of a foreign power.

However, even if such an order does exist, the Times explained that it would be a major breach of the Justice Department’s independence for the White House to compel it to turn over documents relating to an active investigation of itself.

“Any request for information from a top White House official about a continuing investigation would be a stunning departure from protocols intended to insulate the F.B.I. from political pressure. It would be even more surprising for the White House to seek information about a case directly involving the president or his advisers, as does the case involving the Russia contacts,” wrote Michael D. Shear and Michael S. Schmidt.

For McGahn to be searching for evidence that would identify his boss as the subject of a federal probe involving wiretap investigations is, to say the least, highly unusual in Washington.

Veteran journalist Dan Rather said on Saturday that Trump has already weakened our nation’s standing at home and abroad through his wild conspiracy mongering and erosion of the public trust.

Brian Fallon of NBC News noted on Twitter that for the White House to be looking for such evidence amounts to interference in the investigation and only strengthens the case for appointing a special prosecutor.