The Justice Department released a harshly critical review yesterday that shows that prosecutors failed to turn over dozens of pieces of evidence to defense attorneys in the first major terrorism trial after the Sept. 11, 2001, attacks and chronicles "a pattern of mistakes and oversights" so egregious that the government has agreed to abandon the terrorism portion of the case altogether.

A special attorney assigned to review the convictions of three alleged members of a terrorist sleeper cell in Detroit found that the prosecution withheld numerous e-mails, photographs, witness statements and other items that undercut the government's case and should have been turned over to the defense, according to a 60-page memorandum filed in U.S. District Court in Detroit late Tuesday and released yesterday.

The errors and possible misconduct were so rampant that there is "no reasonable prospect of winning" on appeal, according to the filing to U.S. District Judge Gerald Rosen. As a result, prosecutors agreed to a defense request for a new trial and will pursue only document fraud charges against the three defendants, two of whom were convicted of terrorism charges last year.

The review by Craig S. Morford, a federal prosecutor in Cleveland, is particularly critical of the former lead prosecutor in the Detroit case, Richard Convertino, who, among other things, allegedly failed to turn over photographs to the defense and elicited testimony from witnesses that led the judge and other lawyers to believe they did not exist.

Convertino, who has been removed from the case and is the subject of an ongoing criminal probe, told investigators he does not recall the photos and has disputed other allegations against him, according to Morford's review.

"In its best light, the record would show that the prosecution committed a pattern of mistakes and oversights that deprived defendants of discoverable evidence . . . and created a record filled with misleading inferences that such material did not exist," the report says.

The admission of error by the Justice Department comes as the Bush administration is highlighting its anti-terrorism efforts at the Republican National Convention in New York. Attorney General John D. Ashcroft had previously hailed the Detroit prosecution as a major victory in the war on terrorism, and the case was listed as one of the department's "notable achievements" in a report to Congress in January.

Convertino, who has filed a lawsuit against Ashcroft and the Justice Department, declined to comment. His Washington attorney, William Sullivan, said Convertino is a "vigorous and principled prosecutor" who always had "the safety and protection of his community" in mind.

"Even if [Assistant U.S. Attorney] Convertino had knowledge of the materials characterized as being disclosable to the defense, those materials were insubstantial, cumulative and would not encourage the reasonable possibility that a different verdict would have resulted after trial," Sullivan said in a statement.

The Justice Department has secured a number of guilty pleas and convictions in high-profile terrorism cases over three years. But in recent months it lost an important case in which it accused an Idaho man of using the Internet to recruit and raise money for holy war abroad, and was embarrassed by the FBI's erroneous detention of an Oregon man -- a convert to Islam -- for involvement in the Madrid train bombings based on an inaccurate fingerprint match.

"It's just another in a long line of mishaps by this Justice Department in prosecuting the so-called war on terror," said I. Michael Greenberger, a Justice official in the Clinton administration who now heads the Center for Health and Homeland Security at the University of Maryland.

Justice spokesman Mark Corallo said Ashcroft's decision to assign Morford to review the case shows the department's willingness to examine its own shortcomings. "We stepped up to the plate and did the right thing in the interest of justice," he said.

Defense attorneys in the case did not return telephone calls yesterday.

In the first major terrorism trial since the Sept. 11 attacks, two defendants, Abdel-Ilah Elmardoudi and Karim Koubriti, were convicted in June 2003 of conspiring to provide material support to terrorists and document fraud, while a third man, Ahmed Hannan, was convicted of document fraud. A fourth defendant was acquitted.

The general prosecution theory was that the men were part of a fundamentalist "sleeper cell" who had been caught with materials indicating that they had been casing a U.S. air base in Turkey and a Jordanian hospital as possible targets of terrorist attacks.

But the report raises serious questions about the veracity of most of the key evidence and testimony at the heart of the case. It includes strong indications that a videotape and sketches portrayed as terrorist surveillance material may have been nothing more than tourist footage and innocent doodling. Prosecutors also failed to inform defense attorneys that many U.S., Turkish and Jordanian officials had doubts about various aspects of the case, the report said.

The report also raises doubts about the testimony of star prosecution witness Youssef Hmimssa, an admitted credit card fraud artist who alleged the defendants were Islamic fundamentalists involved in terrorist activities.

The central figure in the Morford probe is Convertino.

In one incident, Morford contends that Convertino "made a deliberate decision not to have the FBI take any notes" during debriefing sessions with Hmimssa to limit defense attorneys' ability to challenge his statements. Prosecutors in Detroit and at Justice Department headquarters argued against this unorthodox approach, the memo says.

In another instance, the report alleges that Convertino may have elicited "misleading testimony" from an FBI agent and others, leading Rosen and defense attorneys to believe that photographs that should have been turned over did not exist.

Keith Corbett, Convertino's supervisor and co-counsel, who also was removed from the case, told investigators that "he would not have participated" if he had known about much of the information that was not disclosed to defense attorneys. Corbett declined to comment yesterday.

Staff writer Allan Lengel contributed to this report.

James Thomas, with fellow lawyers Bill Swor, left, and Richard Helfrick, center, talks to reporters in Detroit after they filed a motion to dismiss convictions against three terrorism suspects.