Authorities have found the remains of a 12-year-old girl who went missing after performing in a Christmas concert 34 years ago.

According to CBS News, police announced on Thursday that construction workers in first discovered the remains of Jonelle Matthews, who vanished in Greeley, Colorado, in December 1984.

On December 20 of that year, Matthews had been part of a choir performance at Franklin Middle School. She was last seen at around 8 p.m. that night, when a friend’s father dropped her off at home. The friend was also in the car. Matthews lived with her parents and sister, and was last seen alive entering the ranch-style home. According to the report, her mother was out of town and her father and older sister were at her sister’s high school basketball game. The girl was reportedly missing from the home when her father returned at about 8:30 p.m.

Authorities have not released specifics about how the remains were found, the condition of the body, or a possible cause of death.

Greeley police Sgt. Joe Tymkowych told CBS News that he could not comment at this time on how authorities were able to identify the remains as belonging to the missing girl.

At the time of her disappearance, President Ronald Reagan helped generate national awareness about Matthews’ case. According to CBS News, his administration helped create a national center for missing children along with a hotline to aid in any investigations.

Matthew’s sister Jennifer Mogensen spoke to the Associated Press about the long-awaited development in the case.

“I’m grateful for this closure after 34 years,” Mogensen reportedly said. “It does bring up some old wounds and some more questions, maybe, of what happened. But we’ve received so much love and support already.”

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