Growing up, I heard my parents talk about the grisly 1970 double homicide of their college friend Bill Sproat and Bill’s girlfriend, Mary Petry, near the The Ohio State University campus in Columbus. No arrests were ever made. The murders of Mary and Bill were so violent – reportedly involving a kitchen knife, wire hangers and a bowling ball – that they were compared to the Charles Manson cult killings of the previous year. Manson and his followers killed multiple people in California in 1969 and the savage crimes shocked the nation and turned him into a criminal icon. I wondered: In an age of ever-advancing DNA technology, is there new hope the case could be solved? My parents and I started with a road trip to talk to Mary’s identical twin sister, Martha Petry, who told us she still wants answers.