WASHINGTON — All the witnesses Republicans called in for depositions as part of their impeachment inquiry against President Joe Biden in January said that they knew of no corruption on Biden’s part.

Eric Schwerin, a Biden family friend who partnered with the president’s son Hunter Biden in business and also did bookkeeping for the father, told lawmakers on Tuesday that he was not aware of Joe Biden benefiting financially from his son’s work.

“Given my awareness of his finances and the explicit directions he gave to his financial advisers, the allegation that he would engage in any improper conduct to benefit himself or his family is preposterous to me,” Schwerin said in an opening statement obtained by HuffPost.

Four other Hunter Biden associates also told lawmakers this month that they’d never witnessed improper behavior by the president, nor efforts by his son to entangle him in a foreign business deal.

It’s a continuation of the pattern set in motion last year by House oversight committee Chair James Comer (R-Ky.), who has struggled to prove his accusations that the president enriched himself by participating in his son’s alleged “influence peddling” schemes.

“We have a consistent pattern of witnesses coming in and telling us that Joe Biden just was not involved in any of the business affairs that the Republicans are talking about,” Rep. Jamie Raskin (D-Md.), the top Democrat on the oversight committee, told HuffPost.

Comer said Tuesday that Schwerin’s testimony actually did reveal something bad: that Schwerin, while he was in business with Hunter Biden, provided bookkeeping services to the elder Biden when he was vice president — for free. (Schwerin’s involvement in the family finances has long been known.)

“This guy was doing Joe Biden’s books, paying his electric bills and depositing his paycheck and his income tax refund, and he never charged Joe Biden — that is a gift, that is a clear ethics violation by Joe Biden,” Comer said on Fox News. “There was not a wall between Joe Biden and Hunter Biden and his schemes like the president has always said.”

Ethics rules generally forbid gifts (including discounted goods or services) to executive branch officials, though there are exceptions, including for gifts that are based on a personal or family relationship. It’s possible Schwerin’s bookkeeping would qualify for an exception.

“A gift of free bookkeeping assistance from a family friend would seem to fall within the scope of the personal relationship exception that applies to government employees under applicable ethics gift rules,” Virginia Canter, chief ethics counsel with the group Citizens for Responsibility and Ethics in Washington, said in a statement to HuffPost.

The White House declined to comment.

Nevertheless, commingled bank accounts and free bookkeeping are a far cry from the bribery schemes that Republicans have alleged — including a Ukrainian quid pro quo that supposedly involved $5 million in bribes to the father and son in exchange for official favors. Republicans have obtained thousands of pages of Biden family bank records, and all they’ve revealed so far is that Joe Biden helped his son buy a truck in 2018.

The younger Biden entered into multiple foreign business relationships during and after his father’s time as vice president, including a lucrative contract with a Ukrainian gas company and an ill-fated venture with a company backed by a Chinese energy firm. Hunter Biden wrote in his 2021 memoir that the 2015 death of his brother, Beau Biden, spurred him toward high-paying jobs that fueled his crack cocaine addiction until he sobered up in 2019. Republicans have said that his lack of experience in the energy sector suggests that foreign nationals were only paying him to get to his father.

As for the favorable testimony from Biden associates, it’s not surprising that longtime friends might defend the family from corruption allegations, but they’re doing so under threat of criminal penalty for untruthful testimony while speaking to lawmakers who already have receipts. In other words, if they lied, they could get caught and sent to prison. So their testimony matters.

• Rob Walker told lawmakers last week that he started working with Hunter Biden in 2008. “In business, the opportunities we pursued together were varied, valid, well-founded, and well within the bounds of legitimate business activities,” Walker said in an opening statement. “To be clear, President Biden-while in office or as a private citizen-was never involved in any of the business activities we pursued.”

• Mervyn Yan, a real estate consultant who worked with Hunter Biden in 2017 on possible investments with the Chinese energy company, testified that Joe Biden wasn’t involved in the business, according to a source with knowledge of the deposition, and that he never expected the elder Biden would benefit. Yan’s attorneys said in a letter that their client was “unaware of any involvement President Biden may have had with his son’s business pursuits.”

• Kevin Morris, who became friends with Hunter Biden in 2019 and covered his expenses as he launched an art career, said that he did not have “any expectations of receiving anything from Hunter’s father or the Biden administration in exchange from helping Hunter, nor have I asked for anything from President Biden or his administration.”

• George Bergès, a gallery owner who has sold Hunter Biden’s artwork, said that there was nothing political about his relationship with the president’s son, and that he actually dropped him as a client last year because the political backlash had been such a headache. “When I first met him, I never thought ― I think his dad hadn’t even decided to run, so I never thought he would run, win the nomination, and then be a sitting President,” Bergès said, noting that he had donated repeatedly to Republican Donald Trump’s presidential campaign.

Next month lawmakers will hear from the president’s brother James Biden as well as Hunter Biden. Republicans want to talk to several other people, including Tony Bobulinski, a former Hunter Biden business associate whom the Trump campaign recruited to participate in an event before a 2020 presidential debate.

It’s unclear if Republicans have set a date for interviewing Bobulinski, but it’s possible that his testimony would cast Hunter Biden’s work in a different light.

“I’ve heard Joe Biden say that he’s never discussed business with Hunter. That is false,” Bobulinski said at the 2020 event. “I have firsthand knowledge about this because I directly dealt with the Biden family, including Joe Biden.”