For his book The Blood of Emmett Till, the historian Timothy B. Tyson interviewed Carolyn Bryant Donham, the woman whose brief encounter with Emmett Till in August 1955 led to his brutal lynching at the hands of her husband and brother-in-law. At the time, Donham was a young mother of two boys, and owned and operated a country store in Money, Mississippi, with her then-husband, Roy Bryant. Before Tyson’s interview with her, which took place in 2008, she had never spoken with the media about the case.

According to recovered court transcripts released by the FBI in 2007, Carolyn testified that she was working the cash register on the night of August 24 when Till walked into the store. He flirted with her and made physical advances, then let out a “wolf whistle” as she walked out of the store to retrieve a gun from her car.

But in the interview with Tyson, Donham (by then 72 years old, divorced from Roy Bryant and twice remarried) admitted that she had lied in her court testimony when she said Till had “grabbed her around the waist and uttered obscenities.” Donham said she couldn’t remember what happened the rest of that night. Whatever it was, she told Tyson, “Nothing that boy did could ever justify what happened to him.”

Less than four days after Till’s interaction with Carolyn Bryant, Roy Bryant and his half-brother, J.W. Milam, kidnapped the 14-year-old boy from his great-uncle’s house. In the early hours of August 28, 1955, they beat him severely and shot him in the head. After tying a heavy cotton gin fan to his neck with barbed wire, they threw his body in the Tallahatchie River. Despite their efforts, the body surfaced three days later, so bloated and disfigured that Till had to be identified by a ring on his finger.

Emmett’s mother, Mamie Till-Mobley, had been reluctant to allow her son to travel to Mississippi. Till-Mobley had grown up in the rural South, and knew it was a dangerous place for a young Black boy. After her only child’s mutilated body was transported home, Till-Mobley demanded an open-casket funeral, so the whole world could see what had been done to her son. Over five days, more than 100,000 people lined up to view Till’s body, and Jet magazine published graphic photos that were reprinted all over the world.

Outrage over Emmett Till’s lynching didn’t launch the civil rights movement, which had already begun among African Americans around the country, including the South. In 1954, the U.S. Supreme Court had handed down its verdict in Brown v. Board of Education, declaring that segregated (“separate but equal”) schools for blacks and whites were unconstitutional. But in Mississippi, efforts to overturn the Jim Crow social order had been heavily resisted, and often met with violence. In the months before Till’s murder, Rev. George Lee and Lamar Smith were separately shot and killed in the state after helping organize Black voter-registration drives. Smith was shot in broad daylight, in front of witnesses, as he left the county courthouse in Brookhaven after casting his ballot.

The shocking brutality of Till’s murder, however, and the fact that he was only 14 years old, served to galvanize civil rights workers in Mississippi and beyond. Medgar Evers, then an NAACP field officer in Mississippi, led a secret campaign to find Black witnesses who would come forward in the Till case. Another civil rights leader in the state, Dr. T. R. M. Howard, hired armed guards to protect those witnesses, as well as Till’s mother, during the trial. (Howard already had protection for himself, as he had received death threats.)

During the trial of Roy Bryant and J.W. Milam, Till’s great-uncle Moses Wright identified them in open court as the two men who kidnapped Emmett. After the all-white male jury quickly acquitted the defendants of the murder, Wright and another Black witness had to be smuggled out of the state to avoid reprisals. “It’s getting to be a strange thing that the FBI can never seem to work out who is responsible for the killings of Negroes in the South,” Howard said of the verdict, in a public reproof to FBI Director J. Edgar Hoover. (Howard himself would later flee Mississippi for Chicago after showing up on the “death list” of the Ku Klux Klan, while a white segregationist would assassinate Medgar Evers in 1963.)

A few months after the murder trial, a writer for Look magazine paid Bryant and Milam $4,000 to go on record about how they killed Emmett Till. As they had already been tried once for the crime, the public confession didn’t lead to new charges, but the utter lack of remorse they showed, along with the shocking details of how they had tortured and murdered this 14-year-old boy fueled national outrage. Mamie Till-Mobley went on to become an important civil rights figure in her own right, spending the rest of her life (she died in 2003) speaking out about racial injustice and working to ensure her only child’s sacrifice wasn’t forgotten.

Even beyond his mother’s actions, however, Till’s sacrifice had already had an indelible impact on the future of the civil rights movement. On December 5, 100 days after Till was murdered, Rosa Parks refused to give up her seat on a bus in Montgomery, Alabama. As Parks later said of her actions that day, “I thought of Emmett Till, and when the bus driver ordered me to move to the back, I just couldn’t move.” Her arrest, of course, sparked the now-famous Montgomery bus boycott that turned the struggle for civil rights into a mass movement led by a then-26-year-old minister, the Rev. Martin Luther King Jr.