NAPERVILLE, IL: "Nearly 50 years after a 15-year-old girl was stabbed to death in suburban Chicago, genetic genealogy has led to an arrest in the case. Barry Lee Whelpley, 76, was arrested on Wednesday for the July 1972 murder of 15-year-old Julie Ann Hanson in Naperville, Illinois, the Naperville Police Department said.
Hanson was reported missing after she borrowed her brother's bike to go to a baseball game and never returned home, police said. Hanson's body, stabbed multiple times, was found in a Naperville field, police said. No suspect was identified and the case went unsolved for decades.
Through genetic genealogy, an unknown suspect's DNA left at a crime scene can be identified through his or her family members, who voluntarily submit their DNA to a genealogy database. This allows police to create a much larger family tree than if they were limited to using law enforcement databases like CODIS. Genetic genealogy first came to light as an investigative tool in 2018 when the "Golden State Killer" was arrested through the technique; over 100 suspects have been identified since."
https://www.wbal.com/article/517434/110/arrest-made-in-1972-killing-of-15-year-old-illinois-girl-thanks-to-genetic-genealogy