CHICAGO — A former New York Times reporter who was jailed for nearly three months after refusing to testify in a CIA leak investigation, Judith Miller, spent more than two hours on the stand yesterday as a key prosecution witness in a federal trial of two men accused of conspiring with a Palestinian Arab terrorist group, Hamas.

Ms. Miller’s testimony centered on her unusual role in the 1993 interrogation of a former Chicago-area used-car dealer, Muhammad Salah, at an Israeli prison in the West Bank. The veteran journalist said she arranged to witness the interrogation through contacts at the office of the Israeli prime minister at the time, Yitzhak Rabin, whom she described as a friend.

Ms. Miller said she expected special access to the high-security facility, but got a bit more than she bargained for when the Israeli interrogator asked her to propose questions to be put to Mr. Salah.

“He asked me what I wanted Mr. Salah to talk about. I was a little taken aback,” Ms. Miller said in response to questions from a federal prosecutor, Carrie Hamilton. “I had concerns about being directly or indirectly involved in an interrogation. I just wanted to witness one. I didn’t want to be part of direct questioning.”

Ms. Miller said she offered a general suggestion that Mr. Salah be asked to confirm the Israelis’ claims that he had admitted to knowledge of Hamas’s political structure and its fund-raising operations in America.

Mr. Salah’s alleged admissions of a role in Hamas’s financial affairs led to him spending almost five years in an Israeli jail before he was deported to America in 1997. Those admissions also form the crux of the evidence in the Chicago case, where Mr. Salah and a former Howard University professor, Abdelhaleem Ashqar, are charged with racketeering conspiracy and obstruction of justice.

Ms. Miller was a strong witness for the prosecution, undercutting Mr. Salah’s defense that he was tortured and only admitted to the Hamas activities after more than two weeks of nearly relentless questioning and sleep deprivation. She said Mr. Salah, whom she saw on an audiovisual feed from an adjacent room at the prison, gave no indication he’d been abused.

“I saw no signs of him being tortured or mistreated during the time that I was there and witnessing his behavior,” Ms. Miller said. Mr. Salah “was almost goading him about how Hamas was getting the better of the Israelis. He seemed very relaxed and at ease. … He seemed to take pride in the fact that Hamas had been able to regroup again and again.”

On cross-examination, defense attorneys pointed up some discrepancies in Ms. Miller’s accounts of the episode and attempted to paint her as a shill for the Israeli government.

In a February 17, 1993, story on the front page of the Times, Ms. Miller discussed the evidence against Mr. Salah but did not disclose that she visited the prison or saw the suspect via a video link. She did offer readers uncanny detail about the interrogation, describing it as taking place at “a T-shaped Formica table.” However, she attributed her account to Israeli officials and documents they provided.

When a lawyer for Mr. Salah, Michael Deutsch, suggested that Ms. Miller agreed to “cover up” her visit to the interrogation center so that her readers would not learn of it, the longtime Times journalist took umbrage. “I did not ‘cover up’ the fact. I did not disclose it,” she said. “We often in journalism do not disclose specific sources of information presented as long as they do not contradict the information presented.”

Ms. Miller said she needed some corroboration of the Israeli claims about Mr. Salah and that her editors agreed the prison visit offered that, even if it could not be shared with readers.

Supporters of Messrs. Salah and Ashqar, including about two dozen women in headscarves who sat in the courtroom gallery, seemed deeply skeptical of Ms. Miller’s veracity. When the journalist said she could not remember the name of the editor who signed off on the ground rules for the prison visit, the Muslim women tittered audibly, drawing a stare from the judge, Amy St. Eve.

Under prosecution questioning, Ms. Miller testified that she sought to bring a translator for the Times to the prison, but the Israelis, who said no outsider had ever been allowed at the site before, refused. She said she reluctantly relied on an Israeli government translator to recount the interrogation, which took place mostly in Arabic.

On cross-examination, Mr. Deutsch asked Ms. Miller about a radio interview she did in 1998 in which she said she tape-recorded the interrogation and had it independently translated. The journalist said yesterday that she didn’t remember having taped the session.

As Mr. Deutsch continued, his questions became more speculative, asking Ms. Miller at one point whether she had ever acted as an “asset” for the Israeli intelligence service known as the Mossad.

“No, sir,” Ms. Miller said with an exasperated laugh.

Mr. Deutsch also made reference to the veteran journalist’s departure from the Times last year after 28 years on staff. The defense attorney suggested Ms. Miller was dismissed because she parroted the Bush administration line about Iraq and weapons of mass destruction.

“That’s not why I left the New York Times,” Ms. Miller said, without elaborating.

Ms. Miller eventually disclosed her visit to the interrogation center, describing it in a book she published in 1996, “God Has Ninety-Nine Names.” In the book, she acknowledged the role of Rabin’s office and that she was given the opportunity to ask questions of Mr. Salah through an interrogator. That made her “deeply uncomfortable,” Ms. Miller wrote. “Where was the line between journalism and participating in an official inquiry, and, for all I knew, torture?”

Asked to explain her inclusion of the interrogation in her book, Ms. Miller said circumstances had changed. “Mr. Rabin was dead and since Mr. Salah had been convicted … I thought an appropriate amount of time had passed so I would not be interfering in an ongoing investigation,” she said.

Ms. Miller’s testimony yesterday marked the third time she has crossed paths with the U.S. attorney for the Northern District of Illinois, Patrick Fitzgerald, or his aides.

The Chicago prosecutor, who cut his teeth on terrorism cases in New York, was selected by the Justice Department to oversee the CIA leak investigation that resulted in Ms. Miller’s jailing last summer for contempt. She is likely to be called as a witness next year at the trial of a former White House aide charged with obstructing that probe, I. Lewis Libby.

In a separate and ongoing legal clash that may be headed for the Supreme Court, Mr. Fitzgerald is seeking to obtain Ms. Miller’s telephone records as part of an investigation into who leaked advance word of federal raids against Islamic charities in 2001.

An instructor on journalism ethics, Kelly McBride of the Poynter Institute, said she was troubled by the decision to omit Ms. Miller’s secret visit to the jail from the Times article. “Any time you’re given special access as a reporter to something that a member of the public normally would not gain access to, you’ve got to find a way to reveal the nature of that reporting to the audience,” Ms. McBride said.

The Times did not respond to a request for comment for this article. Ms. Miller also declined to discuss her involvement in the Hamas case with reporters yesterday. However, in response to a question from The New York Sun, she said her appearance was not voluntary. “I was subpoenaed,” she said.

A professor of press law at the University of Minnesota, Jane Kirtley, said it would probably have been futile for Ms. Miller to attempt to resist testifying. However, Ms. Kirtley said the unusual entrée the reporter received and her courtroom testimony could increase the perception that reporters are working hand in hand with government officials.

“Journalists working in this part of the world really need to make it clear they’re not part of the government,” Ms. Kirtley said. “It’s a cautionary tale of how engaging in this kind of newsgathering can eventually come back to haunt you.”