"Last Week Tonight with John Oliver." HBO John Oliver ripped into President Donald Trump on Sunday's "Last Week Tonight" for misleading the American public about whether he had tapes of his meetings with James Comey, the FBI director he fired on May 9.

"James Comey better hope that there are no 'tapes' of our conversations before he starts leaking to the press!" Trump tweeted in May.

In an interview with Fox News last week, however, Trump said he "didn't tape" his talks with Comey but had instead referred to the possibility of tapes in an attempt to force Comey to change his story.

"When he found out that there may be tapes out there, whether it's governmental tapes or anything else, and who knows? I think his story may have changed," Trump said, adding that his move to tweet about the specter of tapes "wasn't very stupid."

Oliver took apart what he called Trump's "extraordinarily stupid" reasoning on the issue, raising the possibility that Trump committed "witness tampering" with his threatening tweet to Comey.

"He didn't just casually admit to misleading the American public," Oliver said. "He also implied that doing so may have swayed Comey's testimony, which, if that was his intent, could constitute witness tampering.

"And on top of all that, he then implied he made Comey tell the truth about their conversations, seemingly verifying Comey's account, which is incredibly damaging to the president," he continued. "So yeah, Trump might actually be right: It wasn't very stupid; it was extraordinarily stupid."

Watch the segment: