A federal judge ruled Monday that a jailed murder suspect can be ordered to answer some questions about his claim that a key witness in the nation's first major post-Sept. 11 (search) terrorism trial lied to the FBI.

U.S. District Judge Gerald Rosen (search) is considering whether to overturn the convictions of two Moroccan immigrants in June 2003, then hailed as an early success in the Bush administration's war on terror. A third defendant was convicted of document fraud; a fourth was acquitted.

The defendants asked the judge to overturn their convictions in part because prosecutors did not release to the defense a letter from an imprisoned gang leader who said the government's key witness lied to federal agents. Prosecutors did not disclose the letter before or during the trial but produced it late last year.

Lawyers for Karim Koubriti (search), 25, and Abdel-Ilah Elmardoudi (search), 38, are seeking to question Milton "Butch" Jones, who is awaiting trial in a federal capital murder case.

In December 2001, Jones wrote federal prosecutors that Youssef Hmimssa (search) spoke about lying to investigators when the two were jailed in adjacent cells. Jones declined to testify when summoned last month, citing his right against self-incrimination.

On Monday, Rosen said Jones cannot be forced to testify about his reasons for sending the letter, but can be required to turn over notes he took at the time he and Hmimssa were jailed near one another and to authenticate the letter and notes.

A lawyer for Ahmed Hannan, acquitted of the terror charge but convicted of fraud, said Rosen's decision raised his hopes of vindicating his client.

"It certainly is not the ultimate that we want, which is a new trial, but it continues to open the door so that that might occur," said James Thomas.

Federal prosecutors did not immediately return a message seeking comment Monday night.

Hmimssa, a self-described scam artist from Morocco, lived briefly with some of the defendants while he was on the run. He was wanted on federal fraud charges in Chicago.

Hmimssa described the defendants as extremists. He testified that one of them told him about the possibility of attacks on the United States one month before Sept. 11.

In the three-page, handwritten letter, Jones said Hmimssa "get to telling me how he lied to the FBI, how he fool'd the Secret Service agent on his case. Youssef get to telling me the roll he played with the terrorists of Sept. 11, 2001 and how he made ID and documents for them to get around any where in the world."