A jury began deliberations Wednesday in the case against a former federal prosecutor and an ex-State Department investigator accused of hiding evidence in the nation's first major terrorism trial after the Sept. 11 attacks.

Former Assistant U.S. Attorney Richard Convertino and Harry Smith III have pleaded not guilty to charges of obstruction of justice, making false declarations before a court and conspiracy. Jurors heard closing arguments Tuesday in the trial, which has lasted three weeks.

For two years, Convertino led the government's case against four North African men in Detroit accused of operating a "sleeper" terrorist cell. Smith helped in the investigation and testified for the government at the trial.

Two of the four men were convicted on terror conspiracy charges in 2003, and Convertino won praise from the Bush administration for his successful convictions. A third defendant was convicted of the lesser charge of document fraud and the fourth was acquitted.

A federal judge overturned the verdicts after prosecutors discovered that some documents that could have aided the defense during the trial were not turned over by the government as required.

Convertino's indictment last year said he and Smith conspired to keep from defense lawyers photographs of a Jordanian hospital that would have undermined the government's argument that the alleged cell made surveillance sketches of the place.

Smith and an FBI agent that the sketch matched the hospital, even though the photographs contradicted that description, the indictment said.

Thomas Cranmer, Smith's lawyer, said the sketch of the hospital turned out to be a minor piece of evidence in the overall case. Defense lawyers also said the government hasn't proven that Convertino intentionally withheld the photos.

"The only motive or intent Mr. Convertino had in this case ... was that he wanted to preserve your safety," William Sullivan, Convertino's lawyer, told jurors during his closing argument.