Special Counsel Robert Mueller must be allowed to finish his investigation, Sen. Marco Rubio (R-Fla.) said on "America's Newsroom."

In recent weeks, Trump's attorneys and supporters have been calling for Mueller to wrap up his probe into alleged collusion between the Trump campaign and Russia.

"This case is essentially over," Rudy Giuliani said on "The Ingraham Angle" on Wednesday. "They're just in denial."

Rubio said Giuliani is just representing his client, but the best thing for Trump -- and the country -- would be for Mueller to finish his work and for the truth to come out.

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"It's not going to take ten years or five years or three years. Let the guy do his work, and it'll all be finished at some point and all the facts will be out there," Rubio said.

He said Trump -- who has repeatedly called the Mueller probe "the greatest witch hunt in American history" -- may be proven right in the end, but the only way for that to happen is for the investigation to unfold.

Rubio added that he's seen no evidence of collusion, and if there was any evidence it likely would have been leaked a long time ago.

"Let the truth come out. I think that's the best thing for the country and the president."

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