David Warren shot and killed Henry Glover in what he said was self defense.
The jury in the case agreed with him, despite prosecutors saying it was unjustified.
Jurors for David Warren's retrial deliberated for 12 hours over two days before acquitting him of a civil rights violation and a firearms charge stemming from the September 2005 shooting death of 31-year-old Henry Glover, whose body was later burned in a car by a different officer.
After the verdict was read, Glover's sister started wailing and had to be carried out of the courtroom. Warren's family fought back tears. Several jurors also wiped away tears as they left the courtroom.
Warren's family embraced each other. "Oh my gosh, I can't even get it in my head," Kathy Warren - David's wife and mother of their five children, who range from 8 to 15 years old - told a relative who hugged her after the verdict.
Warren's lawyers said he would be released today from the courthouse and go home with his family.
Warren testified Monday that he feared for his life when he shot Glover, because he thought he saw a gun in his hand as he and another man ran toward the building he was guarding. Prosecutors, however, said Glover wasn't armed and didn't pose a threat.
Defense attorney Richard Simmons said the case was always about "a policeman's worst nightmare, that split-second decision."
"The benefit of the doubt has to go to the officer," Simmons said, adding that "there's no winners or losers, there's just survivors."
Warren had been sentenced to nearly 26 years in prison after a different jury convicted him of manslaughter in 2010, but an appeals court overturned those convictions and ordered a new trial last year.
A three-judge panel of the 5th U.S. Circuit ruled that he should have been tried separately from four other former officers charged in an alleged cover-up of Glover's death. The panel agreed with Warren's lawyers that the "spillover effect" of evidence about the cover-up, including testimony about the burning of Glover's body and photos of his charred remains, denied him a fair trial.
The jury for Warren's retrial was barred from hearing any testimony about what happened to Glover after a good Samaritan drove the dying man to a makeshift police station. A different officer, Gregory McRae, was convicted in 2010 of burning Glover's body. The 5th Circuit upheld McRae's convictions.
Warren and another officer, Linda Howard, were guarding a police substation at the strip mall on the morning of Sept. 2, 2005, when Glover and another man pulled up in truck. Warren said he screamed, "Police, get back!" twice after Glover and his friend, Bernard Calloway, exited the truck and started to run toward a gate that would have given them access to the building he was guarding.
Calloway, however, testified that Glover was standing next to the truck and lighting a cigarette when Warren shot him. Howard testified Glover and Calloway were running in different directions when Warren opened fire.
Jurors also heard testimony from a former officer, Alec Brown, who said Warren told him shortly after the shooting that he believed looters were "animals" who deserved to be shot. Warren denied saying that.
Earlier on the same morning as Glover's shooting, Warren had fired what he called a "warning shot" at a man who had been riding a bike near the mall. Warren said he knew officers aren't allowed to fire warning shots, but was worried the man intended to do "something stupid" because he had circled the mall several times.
Warren was one of 20 officers charged in a series of federal investigations of alleged police misconduct in New Orleans. His December 2010 conviction was touted as a major milestone in the Justice Department's ambitious efforts to clean up the city's troubled police department.
The same jury that convicted Warren and McRae also convicted a third former officer, Travis McCabe, of writing a false report on the shooting. U.S. District Judge Lance Africk later ordered new trial for McCabe based on new evidence that surfaced after the trial: a different copy of the report that McCabe is accused of doctoring.
The jury at the first trial also acquitted two other former officers of charges related to the alleged cover-up.