In the spring of 1951, the FBI's technical laboratory received a package from the chief of police at Harvale, Massachusetts. The package contained a shirt, stained by blood, and a belt buckle in which several human hairs were caught. Our laboratory was asked to make an analysis to determine if the hair and the blood, were those of a man named John Porter, who had been attacked and killed by a person or persons unknown on the night of May 3rd 1951...