President Trump on Saturday tweeted that the federal inquiry into whether his campaign colluded with Russia to influence the election "should never have started."

He repeated his belief that the investigation, overseen by special counsel Robert Mueller, was a "witch hunt" and that the dossier, which government officials cited in seeking authority to spy on former Trump campaign adviser Carter Page, had been paid for in part by the campaign of Hillary Clinton.

"The Mueller probe should never have been started in that there was no collusion and there was no crime," he wrote It was based on fraudulent activities and a Fake Dossier paid for by Crooked Hillary and the DNC, and improperly used in FISA COURT for surveillance of my campaign. WITCH HUNT!"



The Mueller probe should never have been started in that there was no collusion and there was no crime. It was based on fraudulent activities and a Fake Dossier paid for by Crooked Hillary and the DNC, and improperly used in FISA COURT for surveillance of my campaign. WITCH HUNT! — Donald J. Trump (@realDonaldTrump) March 18, 2018



Research to assemble the document, which has become commonly known as the "dossier," was initially funded by the Washington Free Beacon, as part of opposition research on several Republican candidates. The Clinton campaign and the Democratic National Committee then paid for the research, conducted by the firm Fusion GPS, which at that point was overseen by Christopher Steele, a former British intelligence officer who authored the dossier.

Steele made several allegations in the document, that has since been made public and haven't been verified, that include anti-Trump information involving Russia. For instance, the document said that Trump hired prostitutes to urinate on a bed that former President Barack Obama had slept in.

Republicans have accused the FBI and the Department of Justice of overstepping during Obama's time in office by using information in the dossier to support surveillance on Page.

Trump's tweet follows the firing on Friday of former FBI Deputy Director Andrew McCabe, which he celebrated as "a great day for democracy," but McCabe warned was part of an effort to "slander" him and discredit the Mueller probe. Reports on Saturday said McCabe, like Comey, kept personal memos of his interactions with Trump and he had given them to Mueller. McCabe also interviewed with Mueller's team.

After McCabe's ouster, Trump's personal lawyer, John Dowd, said it was time for Mueller to get fired.