Rudy Giuliani labeled special counsel Robert Mueller’s investigation into possible collusion between the Trump campaign and Russia as “rigged” after it was revealed the FBI used a confidential source during the election to make contact with three Trump campaign associates.

“We are more convinced as we see it that this is a rigged investigation. Now we have this whole new ‘spygate’ thing thrown on top of it, on top of legitimate questions,” Giuliani told CNN’s “State of the Union” on Sunday.

Giuliani said the basis in which Mueller was appointed is “illegitimate,” though he said he previously thought the Russia investigation was legitimate before he joined Trump’s legal team.

“Now I see ‘spygate,’” he said.

Trump, who coined the term “spygate” in relation to the Russia investigation, has ramped up his attacks on the probe amid news of the confidential source. The source was revealed by several news outlets as Stefan Halper, a former University of Cambridge professor.

Giuliani argued that Trump, as commander in chief, has a right to be briefed on the matter.

Earlier this week Trump said the revelation “could be one of the biggest political scandals in history.”