In 1991, flight attendant Nancy Ludwig checked in to an airport hotel near Detroit. The next morning she was found gagged, raped, and tortured. Her husband Arthur never gave up hope that the future would bring enough evidence to close the case.In 1985, fifty-five-year old Margarette Eby, a music professor, met the same grisly death at her cottage in Flint, Michigan. The case went cold-until six years later when the victim's son Mark came upon the...