He is apparently suggesting Russian Federation, the Democrats or the Federal Bureau of Investigation paid for the dossier - or that they all cooperated together to fund the file?
"Workers of firm involved with the discredited and Fake Dossier take the 5th", Trump wrote on Twitter.
Two officials from the firm behind the dossier, Fusion GPS, appeared before the House Intelligence Committee on Wednesday, but answered no questions, and instead invoking their fifth amendment rights against self-incrimination, Bloomberg reports.
The political research firm behind the dossier balked this week at subpoenas from the House Intelligence Committee.
The attorney said the subpoenas violated "the First Amendment rights" of the firm's three founders, adding that they would prevent future candidates "from conducting confidential opposition research in an election".
Steele's work yielded the so-called "dossier", which is a series of memos that outline raw intelligence, much of it unverified, that alleges collusion between Russian agents and the Trump campaign.
Levy, in a recent letter, noted that Simpson spoke recently to the Senate Judiciary Committee but asked that the company be excused from testimony before Nunes' panel as sought by the subpoenas.
Joshua Levy, their lawyer, also accused a "Trump cabal" of carrying out a "campaign to demonize our client for having been tied to the Trump dossier".
The FBI has also entered the equation by investigating the contents of the dossier, which was published online in January by BuzzFeed News.
A source close to the matter told Fox News that Democratic staffers in the hearing were aggressive and ran interference to protect Fusion GPS, often interrupting questions by Republican members on the committee. But even before that, the FBI was aware of the then-unpublished dossier - and in October, they reportedly paid former MI-6 agent Christopher Steele $50,000 to continue his investigation.