At some point shortly before 6:30 a.m. Saturday, some alarming information came to President Trump’s attention.

“Just found out that Obama had my ‘wires tapped’ in Trump Tower just before the victory,” he tweeted. “Nothing found. This is McCarthyism!”

He followed that up with more details — or, at least more tweets. Was it legal for a president to tap a candidate’s phones? Could a lawyer look into this? Just how low had Obama stooped to tap Trump’s phones “during the very sacred election process” (that Trump consistently derided as rigged)?

The response to Trump’s accusations was universal and swift: What?

Former director of national intelligence James R. Clapper Jr. denies that President Trump’s 2016 campaign was wiretapped. (Bastien Inzaurralde/The Washington Post)

In short order, reporters figured out that the genesis for Trump’s assertion was an article at Breitbart, which itself relied on claims made by conservative radio host Mark Levin. The Washington Post’s Robert Costa reported that the article had made its way around the White House’s West Wing on Friday, so it seems likely that this was at least in part the genesis.

So, there you go: Breitbart and Mark Levin were the source of the claims.

Except that Levin essentially cobbled together his theory from various news reports pointing obliquely to the possibility of warranted surveillance. On Sunday morning, this was the tack that deputy press secretary Sarah Huckabee Sanders took in an interview on ABC News.

“The New York Times, BBC, have also talked about and reported on the potential of this having had happened,” Sanders said. “I think the bigger thing is, let’s find out. Let’s have an investigation. If they’re going to investigate Russia ties, let’s include this as part of it.”

So this was the White House line: The mainstream media was the source of the claims.

Except! Our fact-checkers looked at those reports and found that there wasn’t proof of any wiretapping at all. Sanders actually hit on the distinction between the president stating that he’d “just found out” that his phones had been wiretapped and various outlets reporting on the potential of tapping. (Her doing so may have contributed to Trump’s anger Sunday morning that his surrogates weren’t defending him sufficiently on the political talk shows.)

Put another way, those media reports shouldn’t have been the impetus for Trump’s tweets. So then, what was it?

On “Fox and Friends” on Monday, adviser Kellyanne Conway went in a whole new direction. First, she defended Trump’s assertion broadly.

“We have this double standard for anonymous sources. The media loves to use anonymous sources for anything and everything that could possibly be derogatory or negative for this president and his administration, and yet they refuse to give any credibility to such sources when it may be something positive or exculpatory,” she said.

This is a red herring. The media uses anonymous sources — but they know who those people are, granting them anonymity in articles. The media is far more skeptical about using anonymous sources whose identities they don’t know, as they should be. And that’s particularly the case with anonymous sources and invisible evidence offered by a party with a direct stake in the question that’s being addressed. An intelligence official talking to The Post but asking to be anonymous is one thing. The president claiming he has exculpatory evidence that he won’t show is another.

The hosts pressed Conway on the main question. “It sounds like, based on the tweets over this weekend that the president does know that this happened to him,” Ainsley Earhardt asked her. “How does he know that his phone was actually tapped?”

“Let me answer that globally,” Conway replied. “He’s the president of the United States. He has information and intelligence that the rest of us do not.”

Aha! So that’s a pretty clear suggestion that Trump has independent knowledge about tapped phones at Trump Tower. Implying that secret intelligence was the source of the claims.

Sort of implying that, anyway. In classic Conway style, she suggested that Trump had knowledge that we didn’t without explicitly confirming it. “Globally speaking, the president has information that normal Americans don’t” is a pretty effective response to any question about why a president said something. Why did the president say that Arnold Schwarzenegger was fired from “The Celebrity Apprentice”? Well, a president has information that the rest of us do not.

Mind you, several reports suggest that there is no specific intelligence in this case. A spokesman for Obama denied that the former president demanded wiretaps. Obama’s director of national intelligence, James R. Clapper Jr., denied taps targeting Trump during the election. The New York Times reported that FBI Director James B. Comey sought to have the Department of Justice deny the claim specifically. They didn’t.

Shortly after Trump’s initial tweets, press secretary Sean Spicer released a statement about Trump’s claims that provided probably the best explanation for their origin.

“Reports concerning potentially politically motivated investigations ahead of the 2016 election are very troubling,” Spicer wrote. The culprit behind all of this, then?

Reports. Reports are the source of the claim.

But we can narrow that down. What’s the one clear, identifiable source behind those reports, the place the buck stops in terms of drawing national attention to the unfounded idea that the Obama administration illegally targeted Donald Trump’s phones during the 2016 campaign? Simple.

Donald Trump is the source of that claim.

Update: Homeland Security Secretary John Kelly addressed the subject with CNN’s Wolf Blitzer.

“If the president of the United States said that, he’s got his reasons to say that,” Kelly said. “He’s got some convincing evidence that that took place.”

Kelly was not able to say what that evidence might be.