On 21 November 1983, 15-year-old Lynda Mann left her home to visit a friend's house. She did not return. The next morning, she was found raped and strangled on a deserted footpath known locally as the Black Pad. Using forensic science techniques available at the time, police linked a semen sample taken from her body to a person with type A blood and an enzyme profile that matched only 10 percent of males. With no other leads or evidence, the case was left open. (thetvdb.com)