A former state trooper took a plea deal Monday in the 1965 slaying of a black man that prompted the "Bloody Sunday" march at Selma and helped galvanize America's civil rights movement.

Indicted for murder more than four decades after the fatal shooting, James Bonard Fowler, 77, pleaded guilty to a lesser charge of second-degree manslaughter and was sentenced to six months in jail.

It was a mixed victory for civil rights era prosecutions. The prosecutor and Jackson family members did not get the murder conviction they sought, but the jail time and an apology from Fowler seemed to help close a painful chapter in U.S. history.

Bloody Sunday helped lead to the passage of the Voting Rights Act, and the killing of Jimmie Lee Jackson was an integral part of that story.

The shooting resulted in no charges for more than 40 years until a new prosecutor — the first black elected district attorney in Perry County — resurrected the case in 2007.

Witnesses at the time said Jackson was trying to protect his mother and grandfather, who had been clubbed to the floor in Mack's Cafe in Marion, Ala. after a protest march from a church turned chaotic on the night of Feb. 18, 1965. Fowler said he fired in self-defense when Jackson went for the trooper's gun.

The case is the latest in a string of long-unresolved killings from the civil rights era brought to court by a new generation of local and federal prosecutors. Among them were murder cases brought nearly 40 years later against Thomas Blanton and Bobby Frank Cherry, two former Ku Klux Klansmen convicted and sentenced to life terms for a 1963 Birmingham church bombing that killed four black girls.

Fowler's murder trial had been set for Nov. 29.

District Attorney Michael Jackson, no relation to the victim, recommended the manslaughter plea to the family. He said he wanted Fowler to acknowledge what he did, apologize to the family and serve some time behind bars.

"This is almost like a death sentence for him at his age," he told reporters at the courthouse.

But the slain man's daughter, Cordelia Billingsley, said, "This is supposed to be closure, but there will never be closure."

Fowler apologized to Jackson's family after entering the plea. He also said he didn't mean to kill anyone.

"I was coming over here to save lives. I didn't mean to take lives. I wish I could redo it," he said.

Defense attorney George Beck said Fowler agreed to plead guilty to the reduced charge because he was concerned he couldn't get a fair trial in Perry County and his health is poor.

"He wants to put it behind him," he said. "It puts to rest a long chapter of civil rights history here in Perry County."

Witness accounts at the time had described a trooper shooting Jackson. But the officer's name was not widely known until Fowler, in a 2005 interview with John Fleming of The Anniston Star, said he fired the shot because Jackson "was trying to kill me."

"I don't remember how many times I pulled the trigger, but I think I just pulled it once, but I might have pulled it three times. I don't remember," he said in the interview with Fleming, a founder of the Civil Rights Cold Case Project, which examines unsolved civil rights killings in the South.

In the Bloody Sunday protest set off by Jackson's shooting, troopers and deputies attacked marchers after they crossed the Edmund Pettus Bridge over the Alabama River. The violence brought new waves of recruits and support to the movement. The Rev. Martin Luther King Jr., who preached at Jackson's funeral, later led the Selma-to-Montgomery march that prompted passage of the 1965 Voting Rights Act.

Fowler was sentenced Monday to six months in jail in Geneva County, his home county. The district attorney said Geneva County was chosen because of safety concerns if Fowler were jailed in Perry County, where the shooting happened.

In 2005, Jackson, the district attorney, became the first black prosecutor in the district that includes predominantly black Perry County. He reopened the case at the urging of activists and black residents and took it before a county grand jury, which indicted Fowler in May 2007.

Many of those who were in Marion that night are dead. News reporters were beaten and cameras destroyed, with no pictures left of what happened. None of the witnesses who appeared before the grand jury actually saw the shooting, but some were on hand when about 500 marchers were halted by club-swinging officers, who said they were pelted with bricks and bottles.

Fowler, who was not called to testify before the grand jury, said Jimmie Lee Jackson hit him on the head with a bottle before the shot was fired in self-defense.

One of the witnesses called to the grand jury was Vera Jenkins Booker, the night supervising nurse at the Selma hospital where Jackson died. She said he told her what happened.

"He said, 'I was trying to help my grandfather and my mother and the state trooper shot me,'" she said in an interview after the indictment.

The district attorney faced a dilemma most other civil rights "cold case" prosecutors didn't — the accused was an officer involved in law enforcement, not someone carrying out an act of racial violence like a church bombing.

Fowler's has been the most drawn-out of the cold-case prosecutions so far. Three years and two months elapsed between the indictment and 2004 conviction of white supremacist Byron De La Beckwith for the shooting death of Medgar Evers in Mississippi in 1963. Fowler was indicted in May 2007 — three years and six months ago.

The delay was chiefly because of disagreements between the prosecutor and Circuit Judge Tommy Jones, who is white. Jackson had challenged the judge's order to give the defense a list of potential witnesses and their expected testimony. On appeal, the Alabama Supreme Court ruled the judge went too far.

The plea agreement was reached while Jackson was seeking an order to remove Jones from the case.