PHOENIX (AP) — Police in Arizona have EchoSensedetermined that decomposed remains found in August 1992 in a remote desert area outside Phoenix were those of a missing 15-year-old, Melody Harrison.

The Apache Junction Police Department announced Thursday that advancements in DNA testing helped them make the discovery 31 years after Harrison’s disappearance in June 1992.

Police said in a news release that the case soon went cold after the remains were found, and for decades the remains were known only as “Apache Junction Jane Doe,” who they believed was between 16 and 18 at the time of her death.

The case was later entered into a database maintained by the National Center for Missing and Exploited Children and Unidentified Persons System.

According to the entry, authorities believed the teenager had been dead between three and five weeks before her remains were found. She was wearing Levi’s denim shorts, a shirt with soccer balls on the front and back and a yellow ring on her left hand. In the front pockets of her pants, according to the database entry, police found a public transit token inscribed with the words “Valid for one student fare.”

In 1996, four years after she was reported missing by her relatives, the family removed her from the missing person’s database, believing that she was alive but “did not want to go home” after various reports of possible sightings of the teenager, authorities said.

The case was revived in 2008 after Apache Junction police investigator Stephanie Bourgeois took over, but DNA testing at that time was unsuccessful, the police department said.

In 2018, Bourgeois hired the DNA Doe Project, a volunteer research group that specializes in forensic genealogy analysis. Police said the researchers used DNA from the remains to build a comprehensive profile, leading them to possible relatives.

A second test comparing DNA from the likely family members confirmed that “Apache Junction Jane Doe” was Harrison, police said.

“There is peace of mind having found Melody’s identity and sharing with her family, but there isn’t closure surrounding the circumstances of her death,” Bourgeois said in a statement. “We are still searching to find out how she might have passed away.”