(Reuters) - Years before Black Lives Matter protesters roiled the streets of Ferguson and Baltimore, police officers in New Orleans killed two residents and maimed four others on a small bridge on the first Sunday after Hurricane Katrina.

A spent shell casing lies alongside the road on Danziger Bridge in eastern New Orleans, Louisiana November 10, 2005. REUTERS/Lucas Jackson/File Photo

In a courtroom in a New Orleans federal court Wednesday, four of the shooters and one of the supervisors admitted their guilt for the first time. The road to that admission was tortuous, for the families, for the city and for the New Orleans Police Department, in a case that stands among the most significant police civil rights abuses in the United States.

The victims, all black, all unarmed, were trying to survive the hurricane’s wake on Sunday, September 4, 2005, when a pack of officers, believing they were racing to the scene of a police shootout, barreled toward them in a commandeered rental truck. Before the truck screeched to a halt, the driver, an ex-Marine, leaned out the window and pulled the trigger of a handgun. He steered with his right hand, and fired what he later called “warning shots” with his left.

Officers, some black, some white, spilled from the truck and aimed fire at eight residents on the Danziger Bridge. By the time the shooting stopped, Ronald Madison, a 40-year-old with the mental development of a six-year-old, was dead, seven gunshot wounds in his back. On the other side of the bridge, gunshot wounds pierced the slender frame of James Brissette Jr., 17, killing him.

Susan Bartholomew, 38, was trying to crawl on the pavement, her right arm blown apart. Her 17-year-old daughter Lesha, who lay atop her mother to protect her from the bullets, required her own life-saving surgery. So did her cousin Jose Holmes Jr., 19, wheezing for breath and begging paramedics not to give up on him. Father “Big Leonard” Bartholomew Sr. had a gunshot wound in his head. As son “Little Leonard” Bartholomew, 14, raced from the bridge, an officer aimed his gun at the boy’s back and fired twice. He missed.

THE COVER-UP

As paramedics tended to the victims, police began hatching a cover-up. They would plant a gun, invent phony witnesses and craft a fiction portraying the victims as criminals, officers later testified. That morning, as his brother Ronald lay dead, Lance Madison, a onetime NFL wide receiver who stayed back during Katrina to watch over his younger sibling, was handcuffed and charged with attempted murder of police. He spent 25 days in jail on false charges.

This week, 10 years and seven months after the shots on the bridge, officers stood in court and admitted guilt.

They were given prison sentences ranging from 3 to 12 years, decades less than the officers had received after they were initially convicted in August 2011. But a bizarre online scandal involving prosecutors in the U.S. Attorney’s Office put those convictions in jeopardy, opening the door to a second trial.

The families had embraced with relief in 2011. A federal jury convicted the five officers following a trial in which five other officers, in pleading guilty to their own roles, detailed the cover-up.

That closure was short lived. After officers were sentenced to prison, one for 65 years, defense lawyers sought a new trial. The attorneys contended that anonymous online comments criticizing police – many written by Sal Perricone, a New Orleans federal prosecutor not involved in the case – impeded their clients’ chances for a fair trial.

GIRDING FOR A RETRIAL

The bid for a new trial was a long shot, but the presiding federal judge, Kurt Engelhardt Jr., granted it in September 2013, saying the online comments by Perricone and two other federal lawyers impaired justice. The Justice Department acknowledged the comments were improper, but said they had no bearing on the case or the verdict.

Last August, a federal appeals court upheld Engelhardt’s order for a new trial by a 2-1 vote. In February, the full appeals court deadlocked 7-7 on the government’s request that it reconsider the earlier appeals decision. That ruling left everyone girding for a second trial.

Instead, sparing the victims from having to go through another trial, and sparing themselves decades behind bars, the officers pleaded guilty to three federal charges – deprivation of rights, obstruction of justice and conspiracy to obstruct justice. Their sentences:

* Robert Faulcon Jr., 12 years, down from 65 imposed after the jury conviction;

* Kenneth Bowen, 10 years, down from 40;

* Robert Gisevius Jr., 10 years, down from 40;

* Anthony Villavaso II, 7 years, down from 38;

Each was given credit for time served since 2010, meaning Villavaso could be released this year and the other three officers in a few years.

Also sentenced was Arthur Kaufman, a former police sergeant who played a key role in devising the cover-up - including, according to other officers who previously testified, pulling a gun from his garage and claiming it was Lance Madison’s. He pleaded guilty this week to two obstruction of justice charges. Kaufman was given 3 years, down from 6.

“I finally got what I wanted. Someone confessed, ‘I did it,’” said Sherrel Johnson, mother of James “JJ” Brissette Jr., the slain teen, who dreamed of driving to prom in a stretch limousine.

Brissette was close friends with Jose Holmes, the nephew of Susan and Leonard Bartholomew. Brissette bumped into Holmes on the streets of New Orleans after venturing out one day after the hurricane. That Sunday morning, the group of six - the Bartholomew parents, two of their children, plus Jose and JJ - planned to walk over the bridge to buy cleaning supplies for their decrepit hotel rooms, along with medicine for Susan’s ailing mother.

“NOT ABOUT REVENGE”

Lance and Ronald Madison had holed up in their brother Romell’s dental office aside the bridge after the storm and were trying to make their way to the family home about two miles away. They planned to hop on bikes and pedal as far from the misery as possible. They couldn’t pass the flooded streets, and were walking back over the Danziger Bridge to return to the dental office, passing the Bartholomew family along the way, when the rental truck filled with officers barreled toward them.

With Katrina churning toward New Orleans, the brothers had stayed back. Ronald Madison would not leave his two dachshunds behind. Lance stayed to watch over his developmentally disabled younger brother in Lance’s two-story condo. Katrina had forced the brothers to the condo roof, where they begged for a helicopter rescue that did not come. They took five hours to make their way to Romell’s dental office, where they survived until that Sunday morning.

The families’ questioning of the police story helped expose the cover-up. Along the way, the accused officers were paraded as heroes in the city streets, and initial charges filed in state court were dismissed. Now, with the criminal case closed, the families can pursue civil cases brought against the city.

“For the families, it was always about responsibility. It was not about revenge,” said Shannon Fay, a Baton Rouge attorney who helped fight the criminal charges against Lance Madison.

Madison said he was thankful the officers admitted guilt while their elderly mother, Fuki Madison, is still alive.

“I hope and pray that no other family ever has to go through what we have gone through,” he said.