The Oct. 8 beating of Robert Davis, 64, was caught on video by an Associated Press Television News crew covering the aftermath of Hurricane Katrina.
The three officers were charged with battery and other offenses.
Davis spent more than an hour testifying about the beating, which left him lying on the street, hands cuffed and blood flowing from his head and face. Afterward, he told reporters that he still has headaches and back problems and even had to interrupt his testimony to take medicine.
The retired elementary school teacher said he was "a private citizen here on business returning to my home. There was no need for what happened."
Davis said he had returned to the storm-struck city to check on his property and was looking for a place to buy cigarettes in the French Quarter when police grabbed him.
The videotape shows an officer hitting Davis at least four times on the head. Davis twisted and flailed as he was dragged to the ground by four officers. One officer kneed Davis and punched him twice.
CBS News correspondent Byron Pitts reported in October that it is a violation of the New Orleans Police Department's policy to strike a suspect in the head, but Davis was
Officer Stewart Smith had ordered APTN producer Rich Matthews and the cameraman to stop recording. When Matthews held up his credentials, the officer grabbed him, jabbed him in the stomach and delivered a profanity-laced tirade.
Officers Robert Evangelist, 36, and Lance Schilling, 29, were charged with battery against Davis. Smith, 50, was charged with battery against a reporter.
Evangelist and Schilling were fired after the incident; Smith was suspended but remains with the police force.
The video also shows two FBI agents joining the police in subduing Davis. Their role is being investigated by federal officials.
A federal civil rights investigation also was launched.
"Without this videotape, I'm sure this case would be swept under the rug," said Davis' attorney, Joseph Bruno.
Davis has pleaded not guilty to charges of public intoxication, resisting arrest, battery on a police officer and public intimidation. His lawyer said this week he expects the charges will be dropped.