Harry T. Moore and Harriette V. S. Moore were educators and early civil rights leaders in Florida. They married on December 25, 1926, and both worked as teachers in the segregated Titusville Colored School, where Harry became principal in 1927. In 1934, Harry founded the Brevard County chapter of the NAACP and later became the organization's first Executive Secretary in Florida. Their advocacy included efforts to secure equal pay for Black teachers, prosecution of lynchings, and voter registration for Black residents. In 1946, both Harry and Harriette were dismissed from their teaching positions by state authorities because of Harry's activism, after which he became a full-time NAACP employee.
On the night of December 25, 1951 — the couple's 25th wedding anniversary — a bomb made from dynamite that had been planted under the floor of their bedroom in Mims, Florida, exploded. Their daughter, who was home at the time, was unharmed. The Moores were driven roughly 29.8 miles to the nearest hospital in Sanford, Florida, that would treat African-American patients. Harry died en route in the ambulance. Harriette survived long enough to attend her husband's burial before dying of her injuries on January 3, 1952. Their deaths marked the first assassination of an activist during the Civil Rights Movement and the only instance of a husband and wife both being killed during that era.
Five separate criminal investigations have examined the bombing: an FBI investigation beginning the night of the attack and concluding in 1955; a 1978 joint investigation by the Brevard County Sheriff's Office and State Attorney's Office; a 1991 Florida Department of Law Enforcement investigation; a 2004 investigation by the Florida Attorney General's Office of Civil Rights; and a 2008 FBI investigation under the Department of Justice's Cold Case Initiative. These investigations implicated four men described as high-ranking Ku Klux Klan members in central Florida: Earl J. Brooklyn, Tillman H. "Curley" Belvin, Joseph N. Cox, and Edward L. Spivey. Investigators reported that Brooklyn possessed floor plans of the Moore home and had recruited volunteers, and that Belvin was a close, violent associate of his. In 1978, Spivey reportedly gave a deathbed confession implicating Cox, stating that Cox told him he had been paid $5,000 by the Klan to carry out the bombing and then took his own life the day after being confronted by the FBI, on March 30, 1952. Belvin died of natural causes on August 25, 1952, and Brooklyn died of illness on December 25, 1952 — one year to the day after the bombing. Spivey died of cancer in 1980. No arrests were ever made in the case, and the Department of Justice Civil Rights Division formally closed the federal investigation file in 2011.
The bombing prompted immediate local protest in Brevard County and nationwide reactions, including telegrams to President Harry S. Truman and Florida Governor Fuller Warren, a memorial organized by Jackie Robinson in New York drawing about 3,000 people, and an NAACP memorial at Madison Square Garden in March 1952 attended by roughly 15,000 people. Harry Moore was posthumously awarded the NAACP's Spingarn Medal in 1952. The site of their home became a Florida Historical Heritage Landmark in 1999, and Brevard County later established the Harry T. and Harriette Moore Memorial Park and Interpretive Center.