Someone had called to say the Ku Klux Klan was coming to bomb Robert Hicks’s house. The police said there was nothing they could do. It was the night of Feb. 1, 1965, in Bogalusa, La.

The Klan was furious that Mr. Hicks, a black paper mill worker, was putting up two white civil rights workers in his home. It was just six months after three young civil rights workers had been murdered in Philadelphia, Miss.

Mr. Hicks and his wife, Valeria, made some phone calls. They found neighbors to take in their children, and they reached out to friends for protection. Soon, armed black men materialized. Nothing happened.

Less than three weeks later, the leaders of a secretive, paramilitary organization of blacks called the Deacons for Defense and Justice visited Bogalusa. It had been formed in Jonesboro, La., in 1964 mainly to protect unarmed civil rights demonstrators from the Klan. After listening to the Deacons, Mr. Hicks took the lead in forming a Bogalusa chapter, recruiting many of the men who had gone to his house to protect his family and guests.