Another brother, Joseph, said David Mitchell's time locked up for other crimes caused him to become violent.
"There was a big difference in him," Joseph said. "I believe that when they accused him of killing that old woman and he was locked up, that messed with his mind."
The Associated Press could not reach either of the brothers by phone.
Joseph said that David has a split personality and that his alter ego, "Johnny," preys on the weak and elderly.
He was accused of killing 86-year-old Annie Parks of Jenkinjones when he was a teenager. Although Mitchell was acquitted, he was charged a few months later with raping another Jenkinjones resident who was in her 70s and stealing her gun.
Prosecutors dropped the sexual assault charge in a plea deal. He was released from prison in February 2000 but incarcerated that December on a grand larceny charge.
About a year later, 54-year-old Barbara Flake went missing from Jenkinjones, and some suspected Mitchell. State Police Sgt. C.F. Kane said investigators considered David Mitchell a person of interest, but lacked evidence to charge him. They reached out to authorities in New York on Friday to find out if Mitchell has said anything about the 2002 slaying.
About a year after Flake disappeared, David Mitchell was charged in Virginia with kidnapping his ex-girlfriend. The indictment says he stole a vehicle and used it to abduct Saretta Mitchell, and that he drove drunk while evading police. He served eight years in a Virginia prison for that crime.