In 1983, Susan Tice, a 45-year-old mother of four was found raped and stabbed to death in her Toronto home. Four months later, across town, 22-year-old Erin Gilmour returns home from work and is attacked the same way. The women didn't know each other, and both cases remained unsolved for decades. In 2000, DNA profiles from each crime proved their attacker was the same man but didn't reveal his identity. It would take another 20 years, but thanks to genetic genealogy research, the killer was arrested, charged and convicted, bringing a measure of closure for the victims' families.