WASHINGTON ― Republicans quietly issued a subpoena to businessman Devon Archer this week, asking him for documents from his time working with the president’s son Hunter Biden.

House Oversight Committee chair James Comer (R-Ky.) previously asked Archer’s attorney to hand over material related to his contacts with various companies and people, including Joe Biden and officials from the Ukrainian energy company Burisma.

In a Wednesday letter to Archer’s attorney, obtained by HuffPost, Comer and House Judiciary Committee chair Jim Jordan (R-Ohio) said he had ignored previous requests for the documents, forcing them to resort of a subpoena as part of their impeachment inquiry against President Biden.

Archer attorney Matthew Schwartz, a managing partner with the law firm Boies Schiller Flexner, said that the businessman has been cooperating with all “legitimate” investigations.

“He is happy to provide documents to congressional investigators and to testify publicly under oath, and is working with House staff to make that happen,” Schwartz said.

Republicans have put out news releases for most of their subpoenas, but some have been done more quietly, like a request last month to AT&T for years of Hunter Biden’s phone records.

Republicans have struggled to prove their corruption allegations against Biden, namely that he participated in his son’s business deals with foreign nationals from Ukraine and China. Archer and Hunter Biden earned millions from Burisma board positions starting in 2014, when Joe Biden was vice president and the face of U.S. policy toward Ukraine.

The impeachment inquiry seemed to reach a dead end last month when Comer asked President Biden himself to testify. The White House laughed off the request.

With articles of impeachment looking unlikely due to lack of support among the House Republican conference, Comer has talked about making criminal referrals to the Justice Department instead.

Wednesday’s letter from Comer and Jordan said Archer’s records “will also assist in efforts to craft legislative solutions aimed at deficiencies that have been identified in the current legal framework regarding ethics laws and disclosure of financial interests related to the immediate family members of Vice Presidents and Presidents.”

Lawmakers spoke to Archer in a closed-door interview last summer. He testified that Joe Biden was not involved in his various deals with Hunter Biden and foreign nationals. He also said he had not witnessed Joe Biden do any official favors for Burisma, contrary to a debunked Republican theory that Biden used the vice presidency to twist U.S. foreign policy in Burisma’s favor.

Archer did say, however, that he repeatedly witnessed Hunter Biden put his father on speakerphone in the company of their other business partners. Republicans have highlighted the calls as evidence of Joe Biden’s participation in his son’s work, though Archer said the conversations weren’t about business.

“From a blanket perspective, it was always, you know, what’s the ― you know, not necessarily the weather, but, you know, there’s no ― there was no ― and I think you have to understand that there was no business conversation about a cap table or a fee or anything like that,” Archer said, according to the transcript. “It was, you know, just general niceties and, you know, conversation in general, you know, about the geography, about the weather, whatever it may be.”