Washington (CNN) Donald Trump's lawyer Rudy Giuliani claimed Sunday that the President hypothetically could have shot the former FBI director to end the Russia investigation and not face prosecution for it while in office.

Giuliani told HuffPost in an interview that Trump's presidential power extends so far that "in no case can he be subpoenaed or indicted."

"I don't know how you can indict while he's in office. No matter what it is," he said.

The President's attorney said Trump would face impeachment rather than prosecution if he had shot former FBI Director James Comey in the Oval Office to end the Russia probe instead of firing him, which Trump did last May.

"If he shot James Comey, he'd be impeached the next day," Giuliani said to HuffPost. "Impeach him, and then you can do whatever you want to do to him."

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