Fifteen-year-old Alan Perez Watson, who disappeared in 2001, was listed as a runaway until his remains were identified last May. His skull had been found in northwest Atlanta, Georgia in 2009; he’d been shot to death. A suspect was arrested the same month the skull was identified.
That suspect, Dion Renaldo Sims, has been found guilty of murder and sentenced to life plus ten years in prison. I can’t find any other articles about it, though; I don’t have much information.