The Senate Judiciary Committee on Wednesday sought the testimony of a former Bush administration official who helped craft controversial memos outlining U.S. interrogation techniques for detainees.

In a letter to former Justice Department Office of Legal Counsel lawyer Jay Bybee, Judiciary Chairman Patrick Leahy (D-Vt.) noted news reports referencing Bybee’s “regret— over the memos and invited him to testify on “your involvement and your knowledge regarding how these memos were written and approved, what considerations went into that process, who was consulted in that process and the roles of various individuals.—

Numerous lawmakers have called for an investigation into Bybee’s role, and some have sought his impeachment. Bybee is a judge on the 9th U.S. Circuit Court of Appeals.

“By coming forward and testifying before the Committee, you will have the opportunity to amplify or correct these accounts, and explain your role and your views,— Leahy said.

Bybee has come under fire for his role in devising harsh methods for interrogating terrorism suspects. The memos were released by President Barack Obama earlier this month.

Leahy himself has called for Bybee to step down from his judgeship, claiming the former Bush adviser misled the Judiciary Committee during its 2003 review of his nomination.

“There is significant concern about the legal advice provided by OLC while you were in charge, how that advice came to be generated, the considerations that went into it, and the role played by the White House.— Leahy wrote. “I look forward to your cooperation and your testimony.—

Leahy has also lobbied for creating an independent “truth commission— to investigate Bush-era torture practices.