LAPD detectives have arrested a former carnie in the brutal 1978 slaying of a high-flying business executive. Walter Randolph Peartree, 62, was busted at his home in Delaware, Ohio. He is accused of killing James Gentry, 52, on April 10, 1978. The Papermate executive was discovered stabbed to death at his home by a pal. And despite a big reward at the time, the 