Forty-five years after 17-year-old Esther Gonzalez was murdered in California, authorities used advanced DNA technology and forensic genealogy to identify her killer, Lewis Randolph "Randy" Williamson, who had initially been a person of interest but was cleared in 1979 due to limitations in forensic science at that time. Williamson, who died in 2014, passed a polygraph test in 1979, but a post-mortem blood sample yielded a DNA match to semen found at the crime scene. This breakthrough provided the Gonzalez family with long-awaited closure, although their relief is tempered by Williamson's death. The case highlights the power of modern forensic techniques in solving decades-old cold cases.