The Senate Homeland Security and Governmental Affairs Committee voted on Wednesday to issue a subpoena to Blue Star Strategies, a U.S. firm connected to Ukrainian energy firm Burisma, as part of the panel’s probe in to Hunter Biden’s role as a board member.

On an 8-6 party line vote, Republicans — including Sen. Mitt Romney of Utah, who sits on the committee — approved the subpoena.

Committee Chairman Ron Johnson (R-Wis.) announced in February he planned to subpoena the public relations firms for records regarding possible conflicts of interest in Biden’s role as a board member with Burisma.

The National Sentinel reported at the time:

…Johnson…announced he will issue a subpoena to Blue Star Strategies, a consulting firm that is connected to Hunter Biden and Burisma, the Ukrainian gas company where Biden served as a well-paid board member and which hired the firm to fight back against allegations of corruption.

“While we work through those questions, at the suggestion of both Republican and Democrat Committee members, we will instead go straight to the source and compel the same records and an appearance directly from Blue Star Strategies,” Johnson said in a memo to committee members.

The panel wants to know whether anyone at the PR firm improperly used the relationship with the son of the then-vice president and current presumptive Democratic presidential nominee Joe Biden to “influence” U.S. government agencies, Fox News added.

“The subpoena would cover records dating back to January 1, 2013, regarding their work for Burisma Holdings, or individuals associated with Burisma’s founder, Mykola Zlochevsky. He also wants Blue Star CEO Karen Tramontano and Chief Operating Officer Sally Painter for depositions,” Fox News continued.

A letter to the committee from Karen A Tramontano, the co-founder and CEO of Blue Star, questioned why a subpoena is needed when the firm has said it would cooperate with the committee in the past.

“At every opportunity we have indicated to the Committee that it is our intention to cooperate,” she wrote. “Therefore, we are puzzled, despite our willingness to cooperate, why the committee is proceeding to vote on a subpoena.”

She also requested that the committee “take into consideration that we have eagerly cooperated to date and have every intention to continue to do so in the future.”

A committee spokesperson pushed back on those assertions, telling Fox News that “a bipartisan group of committee members suggested that we subpoena Blue Star Strategies, so we authorized that today.”

“The fact is Blue Star has delayed our efforts for more than five months, and even refused to let our staff speak to their attorney until last week–despite the fact that he was speaking with the Ranking Member’s staff,” the spokesperson added. “Their only real efforts came after we noticed this markup, and we know even those have been woefully incomplete.”

The spokesperson noted further that “the American people deserve to know the extent to which the U.S.-based, Democrat-led consulting company leveraged its connections within the Obama administration to try to gain access to and influence U.S. government agencies on behalf of its corrupt client, Burisma.”

Hunter Biden joined the board of Burisma in April 2014. According to reports, he connected Burisma with Blue Star Strategies to help the energy company fight allegations of corruption.