An effort to identify remains of young men killed by John Wayne Gacy in the 1970s has led to a break in an unrelated case of a unidentified teenager found shot to death in San Francisco 36 years ago.

The Cook County Sheriff’s office announced Wednesday that DNA tests revealed a "genetic association" between the remains of the teen and Dr. Willa Wertheimer, who submitted her DNA to the office in 2011.

At the time, Sheriff Tom Dart said he had exhumed the remains of eight of Gacy’s 33 victims who were never identified and asked the relatives of young men who vanished in the 1970s to submit to DNA testing in the hopes of finding a match.

This led to the identification of one of the eight, William George Bundy, within weeks of the exhumations, but the woman’s DNA did not match any of them. Then late last year, the San Francisco Medical Examiner’s office submitted tissue samples of unidentified people who had died there, including from a young man who was shot to death in 1979.

Like the samples from the unidentified Gacy victims, those samples were uploaded into a federal database and Dart’s office was notified in May of a genetic association between Wertheimer and the San Francisco remains. Wertheimer’s half brother Andre "Andy" Drath had disappeared after traveling from Chicago to San Francisco. Dental records, an "Andy" tattoo and records that show he had traveled to San Francisco helped to confirm the identification.

Wertheimer was notified of the match this month.

Drath’s body will be returned to Chicago for burial.

"You should never lose hope in finding your loved one," Wertheimer said in a release issued by Dart’s office. "He could still be living, or at least in your heart can know the peace of bringing him home."

The identification is the latest in about a dozen cases that have been closed as a result of the exhumations of Gacy’s victims. Gacy, one of the most notorious serial killers in American history, was executed in 1994.

The submission of DNA from the dozens of families of missing young men has also helped authorities identify the remains of young men found in Utah and New Jersey. In some cases, the missing loved ones have been found alive, including a man who ran away years ago and was found living in Oregon.

Though no remains found outside the state have been identified as Gacy victims, Dart has said that because the killer traveled extensively, there could be more victims than those found in a crawl space in his house and dumped in a river.

"This breakthrough illustrates that we should never give up on a cold case," Dart said in a news release.

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