A New Orleans police officer convicted of writing a false report about the deadly police shooting of a man in the chaotic aftermath of Hurricane Katrina claims he has new evidence that could clear him.

Lt. Travis McCabe was convicted in December of charges he falsified a report to make it appear that a former officer, David Warren, was justified in shooting 31-year-old Henry Glover in September 2005. Sgt. Purnella Simmons, a government witness, testified that fabricated material was added to her original report without her knowledge.

Simmons couldn't produce her original report, but McCabe's lawyers said in a court filing Monday that they have found a copy she gave Warren in December 2005 that is "identical in substance" to the version McCabe was convicted of falsifying.

Warren's lawyers found the copy in their files after the trial. The discovery provides "overwhelming" evidence that there were never different versions of the narrative in the report on Glover's shooting, McCabe's lawyers wrote.

"The fact that there was always only one version of the report narrative negates the government's entire basis for prosecuting Officer McCabe," they wrote.

McCabe's attorneys are asking U.S. District Judge Lance Africk to set aside his convictions or order a new trial.

"The manner in which the newly discovered evidence exonerates Travis McCabe could not have been planned or designed by anyone," McCabe's lawyers added. "This is simply a case of the truth coming out."

A spokeswoman for U.S. Attorney Jim Letten declined comment Tuesday, saying prosecutors would respond in writing to McCabe's filing.

The jury in December also convicted Warren of manslaughter for shooting Glover without justification and convicted Officer Gregory McRae of burning his body in a car. McCabe, Warren and McRae are scheduled to be sentenced in March or April.

Lt. Dwayne Scheuermann was acquitted of burning the body. Former police Lt. Robert Italiano was cleared of charges he submitted the false report and lied to the FBI.

Prosecutors said Warren shot the unarmed man in the back while guarding a police substation at a strip mall on Sept. 2., 2005. Warren testified he thought he saw a gun in Glover's hand, but his partner that day said Glover wasn't armed and didn't pose a threat.

McRae admitted he burned Glover's body in a car after he was driven to a makeshift police headquarters.

The newly discovered version of the report and the version McCabe was charged with doctoring have some grammatical differences. Both versions describe the chaotic state of New Orleans after Katrina and state that two police supervisors determined Warren was justified in shooting Glover.

All five officers charged in the case testified at trial, describing grueling, dangerous conditions after the Aug. 29, 2005 storm, when thousands of desperate people were trapped in the flooded city. Looting was rampant, bodies rotted in the streets and officers recalled they had no time to write reports or investigate anything but the most serious crimes.