DETROIT — A Pulitzer Prize-winning reporter seeking to protect the identity of unnamed sources asked two judges yesterday to stop a deposition intended to reveal who leaked information about an investigation of a terrorism prosecutor.

David Ashenfelter of the Detroit Free Press is scheduled for a deposition Oct. 16, weeks after a federal judge said he couldn’t claim a reporter’s privilege to avoid the subpoena.

Richard Convertino, who handled the first major terrorism trial after 9/11, wants to know who in the U.S. Justice Department supplied information about an ethics investigation for a Free Press story in 2004.

He is suing the government, claiming his privacy rights were violated.

Ashenfelter’s resistance to answering questions about his sources is moving on two separate tracks.

In Detroit, he’s asking U.S. District Judge Robert Cleland to shift the First Amendment fight to Washington, where another federal judge is overseeing Convertino’s civil lawsuit.

In Washington, Ashenfelter wants U.S. District Judge Royce Lamberth to put any deposition on hold. Among the reasons, he said Convertino should be forced to show he’s exhausted all other ways to get the information.

The Free Press hopes Lamberth also would recognize Ashenfelter’s right to protect his sources.

“Every forced disclosure of a journalist’s confidential source rips a new and ominous hole into the fabric of press freedom,” lawyer Herschel Fink said in a court filing in Washington.

Convertino is “not seeking disclosure of sources to protect national security or because someone has published leaked grand jury testimony. This is just about improving his chances of a big payday from the government,” Fink said.

He said Ashenfelter would refuse to answer questions on Oct. 16, “likely leading to a contempt citation.”

Convertino’s attorney, Stephen Kohn, said he would fight the attempt to stop the deposition.

“The Detroit Free Press should not assist corrupt government officials in covering up misconduct,” he said in an interview.

“They lost. Game over,” Kohn said, referring to Cleland’s decision in August that Ashenfelter must testify.

Ashenfelter wrote a story that said Convertino was being investigated by the Justice Department’s Office of Professional Responsibility. The story listed many allegations and attributed the information to department officials who asked for anonymity because they feared repercussions.

Convertino was a celebrated prosecutor until three terrorism convictions in Detroit in 2003 were overturned at the government’s request because evidence was withheld. He resigned in 2005.

Convertino and a former State Department investigator were indicted for their work on the case, but a jury acquitted them in October 2007.

Ashenfelter won a Pulitzer Prize, journalism’s top prize, at The Detroit News in 1982.