WASHINGTON (AP) — Former President Bill Clinton and former Secretary of State Hillary Clinton said Tuesday that they will refuse to comply with a congressional subpoena to testify in a House committee’s investigation of Jeffrey Epstein.

The Clintons, in a letter released on social media, slammed the House Oversight probe as “legally invalid” even as Republican lawmakers prepared contempt of Congress proceedings against them. The Clintons wrote that the chair of the House Oversight Committee, Republican Rep. James Comer, is on the cusp of a process “literally designed to result in our imprisonment.”

“We will forcefully defend ourselves,” wrote the Clintons, who are Democrats. They accused Comer of allowing other former officials to provide written statements about Epstein to the committee, while selectively enforcing subpoenas against them.

Comer said he’ll begin contempt of Congress proceedings next week. It potentially starts a complicated and politically messy process that Congress has rarely reached for and could result in prosecution from the Justice Department.

“No one’s accusing the Clintons of any wrongdoing. We just have questions,” Comer told reporters after Bill Clinton did not show up for a scheduled deposition at House offices Tuesday.

He added, “Anyone would admit they spent a lot of time together.”

Clinton has never been accused of wrongdoing in connection with Epstein but had a well-documented friendship with the wealthy financier throughout the 1990s and early 2000s. Republicans have zeroed in on that relationship as they wrestle with demands for a full accounting of Epstein’s wrongdoing.

Epstein was arrested in 2019 on federal sex trafficking and conspiracy charges. He killed himself in a New York jail cell while awaiting trial.

“We have tried to give you the little information we have. We’ve done so because Mr. Epstein’s crimes were horrific,” the Clintons wrote in the letter.

Multiple former presidents have voluntarily testified before Congress, but none has been compelled to do so. That history was invoked by President Donald Trump in 2022, between his first and second terms, when he faced a subpoena by the House committee investigating the deadly Jan. 6, 2021, riot by a mob of his supporters at the U.S. Capitol.

Trump’s lawyers cited decades of legal precedent they said shielded an ex-president from being ordered to appear before Congress. The committee ultimately withdrew its subpoena.

Comer also indicated that the Oversight committee would not attempt to compel testimony from Trump about Epstein, saying that it could not force a sitting president to testify.

Trump, a Republican, also had a well-documented friendship with Epstein. He has said he cut off that relationship before Epstein was accused of sexual abuse.