MORRIS, Ill. (AP) — DNA experts have identified the remains of a woman found shot to death in an Illinois ditch almost 50 years ago.

The DNA Doe Project said in a news release Thursday that their investigators had identified the woman as JoAnn “Vickie” Smith of Ohio.

Smith was found in a ditch near Seneca, Illinois, in 1976. She had been shot in the head. But police couldn’t identify her and closed her case after two months.

She was buried in an unmarked grave but the Grundy County Coroner’s Office reopened her case in 2017 and had her remains exhumed in 2018 in hopes that modern forensics could identify her.

The coroner’s office reached out to the DNA Doe Project, a nonprofit organization that works to identify unknown subjects.

The group’s genealogists spent 4 1/2 half years trying to establish her family tree. The work was complicated because Smith had been adopted and even though investigators were able to match her DNA profile to biological relatives, most of them didn’t know she existed.

Investigators finally built a branch of Smith’s family tree that led to three sisters. One of them was her birth mother. Final confirmation of her identity was made through adoption records on file in probate court in Cincinnati, DNA Doe Project officials said.

The news release did not say where Smith was from in Ohio.