House Republicans are mulling whether to issue a subpoena to compel former FBI Director James Comey to testify on Capitol Hill about the bureau’s actions before the 2016 election.

A Republican House Judiciary Committee aide said the committee invited Comey to come in for a closed-door transcribed interview but Comey declined the invitation. Republicans are now prepared to issue a subpoena to compel his appearance, the aide told Fox News.

Comey’s lawyer, David Kelley, had sent a letter to the House Judiciary and Oversight Committees this week refusing a closed door deposition but saying the former director was open to public testimony.

“Mr. Comey respectfully declines your request for a private interview,” Kelley said in the letter. “He would, however, welcome the opportunity to testify at a public hearing.”

Comey testified in public last year before Congress after he was fired by President Trump. Since then, the former FBI director has written a book and become an outspoken critic of the president.

Republicans want to know more about decisions made by the bureau as it opened up an investigation into Russia’s attempted interference in the 2016 election and whether anyone associated with Trump helped them.

A committee aide could not say when the hearing would take place. It comes as Deputy Attorney General Rod Rosenstein is expected next week, likely Thursday, for a closed-door transcribed interview.

“There are many questions we have for Mr. Rosenstein, including questions about allegations made against him in a recent news article,” House Judiciary Committee Chairman Bob Goodlatte, R-Va., said last week. “We need to get to the bottom of these very serious claims.”

Rosenstein has been targeted by Republicans for months and frequently finds himself in the political crosshairs due to his role overseeing the special counsel's Russia probe.

His future at the Justice Department has been in jeopardy after The New York Times reported last month that Rosenstein discussed wearing a "wire" to tape Trump and pursuing his removal from office in meetings and conversations with Justice Department and FBI officials. Rosenstein has disputed the characterization of those comments.

The White House has said the president wants to meet with Rosenstein about these issues, but that meeting was pushed off amid the attention over the allegations against Supreme Court nominee Brett Kavanaugh. On Tuesday, Trump was asked about Rosenstein, and said “we spoke” and things are “moving along nicely.”

Also Wednesday, Fox News has learned former FBI general counsel James Baker appeared on Capitol Hill for a closed-door deposition with investigators from the House Oversight and Judiciary Committees.

Baker, a close aide to then director Comey, abruptly left the bureau in December. He is believed to have information related to allegations of FISA abuse during the campaign, as well as the infamous dossier of unverified claims about Trump's relations with Russia.