Updated | Oct. 30, 22:00 p.m.

Donald Trump has, for years, treated the lurid fantasies and conspiracy theories that animate the far-right imagination as fact, but that tendency reached new heights on Saturday, as he speculated wildly about the F.B.I. director’s announcement that investigators plan to examine a collection of emails from Hillary Clinton’s aide, Huma Abedin.

At a rally in Colorado, Trump insisted, without basis, that F.B.I. director James Comey’s vaguely worded letter to Congress must mean that “now the evidence is so overwhelming — because they wouldn’t have done this unless the evidence was overwhelming.”

“I will tell you, without knowing anything,” Trump told supporters in Phoenix a few hours later, “the only reason that they did this action that you saw yesterday was: very, very serious things must be happening, and must have been found — very, very serious things, very, very serious things.”

In fact, the F.B.I. director has no idea if there is anything at all related to Clinton’s use of a private email server in the thousands of Abedin emails discovered on a laptop she shared with her estranged husband, Anthony Weiner — who is now under federal investigation for allegedly sending sexually explicit messages to a minor — since investigators have not yet read any of the messages.

Comey’s initial notification to Congress, which led Trump to pronounce Clinton’s use of private email server “worse then Watergate,” failed to note what the director made clear in an internal memo to F.B.I. employees leaked to the Washington Post: agents are still “seeking access” to the emails and taking “steps to obtain and review them.”

As of Saturday night, Michael Isikoff of Yahoo News reported, “the F.B.I. had still not gotten approval from the Justice Department for a warrant that would allow agency officials to read any of the newly discovered Abedin emails.”

(On Sunday night, the F.B.I. did obtain a warrant to examine the Abedin emails on Weiner’s computer, Pete Williams of NBC News reported. Agents plan to use an automated system to see if the emails are merely duplicates of messages already examined, Williams said. “Officials say if this all goes quickly, and nothing potentially classified is found, it is possible that the F.B.I. could come out and say so within the next few days,” he added.)

As Matthew Miller, a former public-affairs director at the Justice Department, told the New Yorker, Comey’s initial statement was damaging because, “The public always assumes when it hears that the F.B.I. is investigating that there must be something amiss. But there may be nothing here at all.”

Seeking to stem the flow of misinformation, and conflicting reports in leaks to the press, four Democratic senators — Patrick Leahy, Dianne Feinstein, Ben Cardin and Tom Carper — wrote to Comey and his boss, Attorney General Loretta Lynch, demanding a briefing by Monday on what, exactly, is known about the Abedin emails.