Harriette and Harry T. Moore, circa 1931. Harriette is holding the couple’s infant daughter, Evangeline. Another daughter, Annie, stands in the foreground. (Family photo)

Evangeline Moore, who sought to preserve the often-forgotten legacy of her activist parents, whose deaths in a 1951 Christmas bombing at their home in Florida were called the nation’s first civil rights assassination, was found dead Oct. 26 at her home in New Carrollton, Md. She was 85.

Her son, Drapher “Skip” Pagan Jr., said she died sometime after going to bed on Saturday. The cause has not been determined.

Ms. Moore was working for the federal government when she boarded a train in Washington on Dec. 26, 1951, to join her parents — Harry and Harriette Moore — for a holiday celebration at their home in Mims, Fla.

Only when she stepped off the train a day later did she learn of the family tragedy that sparked international outrage and inspired a poem by Langston Hughes.

“They’re the only husband and wife who died in the civil rights struggle,” Ben Green, the author of “Before His Time: The Untold Story of Harry T. Moore, America’s First Civil Rights Martyr,” said Wednesday in an interview.

Evangeline Moore in 2011. (Bill O'Leary/The Washington Post)

Harry Moore had been an advocate for racial justice in Florida since at least 1934, when he formed a chapter of the NAACP in Brevard County, midway between Jacksonville and Palm Beach on Florida’s east coast. The Moores were teachers and administrators in black schools of Brevard’s segregated education system.

Working with a civil rights lawyer and future Supreme Court justice, Thurgood Marshall, Harry Moore filed suit in 1937 over disparities between the salaries of black and white teachers in Florida.

Moore later became state secretary of the NAACP and, in 1944, organized the Florida Progressive Voters League, which registered more than 100,000 black citizens to vote, giving the state the highest proportion of African American voters in the South. Beginning in 1945, Moore began to investigate cases of police brutality and lynchings throughout Florida, sending affidavits to Marshall and other civil rights leaders.

Evangeline Moore helped her father work on his speeches and typed the letters he sent to Marshall and other officials.

The Moores were fired from their jobs by the all-white Brevard County school board in 1946, but they continued their activism. On Christmas Day in 1951 — also their 25th wedding anniversary — the Moores had just returned home from a celebratory dinner.

Not long after the lights were turned out, there was an explosion that was heard more than four miles away. A bomb had gone off directly under the Moores’ bedroom.

Harry Moore’s mother and Evangeline’s older sister, Annie, also were in the house but survived without serious injury. Neighbors took Harry Moore to the closest hospital that would treat African Americans, 30 miles away. By the time they arrived, he was dead.

For the funeral, flowers had to come from Miami, 220 miles away, because local florists refused to deliver to a black church. Nine days after the bombing, Harriette Moore died of her injuries.

The FBI was brought into the investigation. A member of the Ku Klux Klan in nearby Orlando committed suicide one day after he was questioned, but no one was charged with the killings.

As a gesture of family strength, Evangeline and her sister, Annie, agreed that they would never betray any outward sign of grief, and they rarely spoke of their parents’ deaths. Annie Moore, who became a teacher, died in 1972.

Only since the 1990s, when journalists and historians began to examine the story of her parents, did Evangeline Moore take a public role in preserving the memory of her family’s contributions to the civil rights movement.

“For Evangeline, the first tragedy was that they were murdered,” Green said. “The second was it was never solved. The third was that people don’t know about it.”

The Moores’ names are not inscribed on the Civil Rights Memorial in Montgomery, Ala., which commemorates only those civil rights workers killed after the U.S. Supreme Court’s landmark Brown v. Board of Education decision of 1954.

“Harry Moore was doing the exact work that was later carried on by Medgar Evers, Dr. Martin Luther King Jr. and Jesse Jackson,” Bill Gary, an NAACP official and board president of the Harry T. & Harriette V. Moore Cultural Complex in Mims, told the Baltimore Sun in 2006. “He was a pioneer of the modern civil rights movement.”

Juanita Evangeline Moore was born Sept. 3, 1930, in Mims. She said her father would not let his daughters attend the local movie theater because they would have to sit in the segregated balcony.

“We were not allowed on public transportation because we had to sit in the back of the bus,” Ms. Moore told Florida Today newspaper in 2005. “So Daddy took us everywhere, even to college and back.”

She came to Washington after graduating in 1951 from Bethune-Cookman University in Daytona Beach, Fla.

After working at the Labor Department, Ms. Moore became an administrator at the State Department. She retired in 1995 from what is now the Epilepsy Foundation of the Chesapeake Region.

Her first marriage, to Drapher Pagan, and two later marriages ended in divorce. Besides her son, of Laurel, Md., survivors include a grandson.

A documentary film about Harry Moore, “Freedom Never Dies,” was shown on PBS in 2001. Ms. Moore returned to Mims over the years to attend civil rights forums and to commemorate the opening of a memorial park and a replica of her parents’ house.

In 2006, when Florida Attorney General Charlie Crist was running for governor, he announced that his office had “resolved” the Moore killings, placing the blame on four long-dead Klansmen. Green and other investigators said Crist’s office had turned up no new evidence, and the case remains officially unsolved.

For years, Ms. Moore said little about her family’s ordeal, yet she never forgot her mother’s final words.

“My mother told me from her deathbed that she never wanted me to ever think about hating white people — or anybody else,” Ms. Moore told the Orlando Sentinel in 2009, “because it would make me ugly, and she didn’t want me to be an ugly woman.”