William Carroll “Billy” Isaacs was the younger brother of Carl Isaacs, born around 1958. The family grew up in unstable conditions, with their father abandoning them and their mother working long hours. Billy suffered early petty crime arrests; by age five, he was caught shoplifting and disciplined by authorities. While Carl faced adult convictions, Billy was placed in the Victor Cullen reform school due to juvenile burglary charges. In April 1973, he escaped and joined his brother's prison breakout.

Billy linked up with his brother Carl, Wayne Coleman, and George Dungee after escaping on May 5, 1973. Days later, near McConnellsburg, PA, Coleman and the others kidnapped and fatally shot 19-year-old Richard Miller to steal his car. Billy was present during these deadly events.

On May 14, 1973, the group invaded the Alday family home in Donalsonville, Georgia. Billy remained present while his brother Carl, Coleman, and Dungee methodically executed six family members, stole belongings, and raped Mary Alday. He provided key eyewitness testimony at trial, describing violent details of the crimes.

Billy avoided a murder trial by agreeing to testify against Carl, Coleman, and Dungee. In January 1974, Gerald Saunders and others used his testimony to secure convictions against his brothers. The prosecution described Billy as “the state’s most damaging witness,” which helped seal death sentences (though later reduced for two defendants). After cooperating, he pleaded guilty to lesser charges of armed robbery and burglary and was sentenced to 40 years, later released in 1993. Released in 1993, Billy relocated to Florida. He lived a more anonymous life until passing away on May 4, 2009, at around age 51.