The 'Washington Post' reported: "[US] President [Donald] Trump on Saturday angrily accused former president Barack Obama of orchestrating a 'Nixon/Watergate' plot to tap the phones at his Trump Tower headquarters last fall in the run-up to the election.
"While citing no evidence to support his explosive allegation, Trump said in a series of five tweets sent Saturday morning that Obama was 'wiretapping' his New York offices before the election in a move he compared to McCarthyism. 'Bad (or sick) guy!' he said of his predecessor, adding that the surveillance resulted in 'nothing found'."
An Obama spokesman gave an emphatic, but noticeably limited response: "A cardinal rule of the Obama Administration was that no White House official ever interfered with any independent investigation led by the Department of Justice. As part of that practice, neither President Obama nor any White House official ever ordered surveillance on any US citizen. Any suggestion otherwise is simply false."
With no comment yet from the FBI or Justice Department, the possibility remains that Mr Trump was under some sort of surveillance in the course of an intelligence investigation.
A showing of probable cause to a court would have been required to obtain a wiretap of the type Mr Trump alleged.
In the course of less than a week, we've gone from "Trump presidency on the rocks" to "What a normal speech!" to "How many Trump associates had contact with the Russians, and why did they lie about it?" to "Trump was bugged, really?!?"
There are several explanations - not necessarily mutually exclusive - for the latest outburst from the US president.
First, he is increasingly out of touch with reality. Just as he obsessed over the crowd size at his inauguration and the upward of three million fictional illegal voters, Mr Trump's mammoth ego cannot take the daily drumbeat of attacks and accusations.
When adversity strikes - as it did with new allegations concerning Attorney General Jeff Sessions, who was forced to recuse himself from any campaign-related investigation - he becomes unhinged and paranoid. He can stick to a teleprompter speech for an hour, but soon reverts to form.
A variation on the first possibility would be that Mr Trump correctly realises the intelligence community has a good deal more information on what contacts his associates had with Russians than he does.
A 'New York Times' story last week confirmed that the intelligence community also has intercepts of Russian officials discussing their contacts with Trump associates.
Mr Trump, under this theory, is panicked. An exaggerated, unsupported claim from a right-wing provocateur and gadfly, Mark Levin, that Mr Trump was directly wiretapped is enough to set him off into a Twitter frenzy. As they said about Richard Nixon, even paranoids have enemies.
Another explanation is that Mr Trump, as he does when things go wrong (the Sessions recusal, disarray on tax and healthcare legislation, accusations about his foreign holdings), deliberately creates distractions. He'd rather the media chatter about whether he is sane than focus on the need to obtain his taxes to determine what connections he and his family have to Russia.
And finally, it is possible that he is right that Trump communications were under investigation - but only up to a point. We go back to a story from late October 2016 in which FBI officials allegedly investigated a connection between computer servers owned by the Trump Organisation and the Russian Alpha Bank. 'The New York Times' reported that there could be an "innocuous explanation" for 2,700 so-called look-up messages sent from Alpha servers to Mr Trump's. This does not necessarily mean the FBI or anyone else was "wiretapping" Trump Towers, but we have yet to find out the extent of its investigation and whether, for example, the FBI discovered additional ties between Trump associates and Kremlin allies.
Apart from the server story, news reports have suggested, as a 'Time' story did, that "as major banks in America stopped lending him money following his many bankruptcies, the Trump organisation was forced to seek financing from non-traditional institutions. Several had direct ties to Russian financial interests in ways that have raised eyebrows." (Mr Trump denies he has any ties to Russia. "I can tell you, speaking for myself, I own nothing in Russia. I have no loans in Russia. I don't have any deals in Russia," he said recently, leaving open the possibility that he and/or his sons have ties to Russians operating outside of Russia.)
After Mr Trump's Twitter outburst, some lawmakers, like Republican Senator Ben Sasse, chose to take him "seriously" - that is, calling for proof of his claims.
Others argued that his accusations only underscored the need for a definitive, independent investigation conducted by either a commission with subpoena power or a special prosecutor named by the deputy attorney general (Mr Sessions, who is recused, could not do so).
Realising their error in inviting more scrutiny, White House press secretary Sean Spicer tried to walk back the allegations yesterday morning. He called for Congress, which is already investigating Mr Trump's Russia connection, to look into improper surveillance during the campaign. He almost begged the press to drop it, saying that no further remarks on the topic would be forthcoming. Good luck with that.
Mr Trump inadvertently emphasised that at the core this is about whether the intelligence community has discovered the president of the United States is compromised.
That cannot very well be left solely to congressional partisans or to a Justice Department that reports to him.