President Trump asserted on Saturday that special counsel Robert Mueller‘s investigation into possible collusion between the Trump campaign and Russia should never have been opened in the first place.

“The Mueller probe should never have been started in that there was no collusion and there was no crime,” Trump wrote on Twitter.

“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 tweet came hours after Trump’s lawyer, John Dowd, released a statement calling on Deputy Attorney General Rod Rosenstein, who oversees Mueller’s investigation, to shut down the probe.

Dowd initially told the Daily Beast that the statement was issued on behalf of Trump, but later reversed course, saying it was given in his personal capacity.

Still, Trump has repeatedly lambasted Mueller’s investigation as a “witch hunt,” arguing that there was no improper contact or coordination between his campaign and Moscow. He reportedly sought last summer to have Mueller fired, but backed down from that position after White House counsel Don McGahn threatened to resign.

Trump’s tweet on Saturday night also came a day after Attorney General Jeff Sessions fired former FBI Deputy Director Andrew McCabe, arguing that McCabe misled congressional investigators and leaked information to the press.

McCabe swiftly pushed back on those charges, saying that his ouster was politically motivated and intended to undercut Mueller’s investigation into Russian election meddling.