WASHINGTON ― Rep. James Comer (R-Ky.), who chairs the House oversight committee, has formally asked President Joe Biden to testify in the impeachment inquiry against him led by Republican lawmakers.

In a letter to Biden on Thursday, Comer said “it is in the best interest of the American people” for the president to answer questions about whether he was involved in his son Hunter’s foreign business deals.

The White House responded by pointing to a social media post from last week where Biden spokesperson Ian Sams wrote “LOL,” alongside a “facepalm” emoji, after Comer first said he’d seek Biden’s testimony.

“Comer knows 20+ witnesses have testified that POTUS did nothing wrong,” Sams wrote on March 20. “He knows that the hundreds of thousands of pages of records he’s received have refuted his false allegations.”

The request for Biden’s testimony is something of an admission that the investigation has hit a dead end. It’s unlikely the House will vote on articles of impeachment against Biden, and Comer has recently talked up criminal referrals to the Justice Department as an impeachment alternative.

Several of Hunter Biden’s former business partners have testified that Joe Biden did not participate in his son’s moneymaking schemes, but they described occasions when Joe Biden greeted his son’s associates in person or made small talk on a speakerphone call.

Comer said the witness testimony and other evidence showed Biden was “indeed involved in these pay-for-influence schemes” and that he had been “repeatedly untruthful regarding a matter relevant to national security” and his own fitness to serve as president.

In particular, Comer cited testimony from Tony Bobulinski, who told lawmakers in a closed deposition and during a public hearing that he met Joe Biden in 2017 when he and Hunter and James Biden, the president’s brother, were cooking up a deal with a Chinese energy conglomerate.

Bobulinski said he met with Joe Biden “multiple times to discuss the broad contours of business dealings” in 2017, but by his own account, he had two conversations with the president, and neither was about the deal at hand. The second occurred while Biden was walking to his car after making a speech.

“When I went backstage, it was, as you can imagine, you know, it was ― it was a tight space, there were a lot of people getting, you know, just water and having different discussions,” Bobulinski said. “But, you know, in the walk out to the car, you know, he thanked me. And I just remember a comment of, ‘Hey, you know, look out for my brother and son and, you know, thank you for what you’re doing’ kind of thing.”