CHICAGO (AP) — An effort to identify the remains of young men murdered by serial killer John Wayne Gacy in the 1970s has led to a break in an unrelated case of a previously unidentified teenager found shot to death in San Francisco 36 years ago.

The Cook County Sheriff’s Office will announce Wednesday that tests have revealed a “genetic association” between the teenager and the DNA of a woman whose half brother, Andre Drath, went missing decades ago.

The sheriff asked relatives of missing teens to submit DNA to determine if it matched unidentified Gacy victims, and the woman submitted hers in 2011.

The sheriff’s department submitted the DNA to a federal database. The match was discovered after tissue samples submitted to a lab by the San Francisco Medical Examiner’s Office were examined late last year.