DNA and the discovery that dental records were submitted upside down have led to the identification of a Utah John Doe found dead in 1983 — and the remains belong to a 17-year-old boy who went missing four months earlier.

Robby Lynn Peay ran away from a youth treatment center in Salt Lake City on October 7, 1982, and police in his hometown, Provo, were called to head up the missing persons case, KSL reported.

When a body was found on February 12, 1983, in Arches National Park, investigators thought they might have found Peay. The victim, dubbed John Doe, had been shot in the back of the head, but despite the similarity of the victim to Peay, decomposition prevented a positive match. Decomposition — and dental records that didn’t match up.

Months later, Peay’s truck was found abandoned near Lake Powell, 350 miles away.

John Doe was buried in a Moab cemetery, while a headstone for Peay marks an empty grave in Provo.

The first break in the case came in 2018 when a Provo officer recovering from surgery was asked to look at some of the department’s older cases. He looked Peay’s case again, comparing the missing boy to another body found in another state. That didn’t pan out, but a forensic dentist asked to take a look noticed something.

Peay’s dental x-rays, sent to a national database for missing persons, were entered into the database upside down. When that was corrected, the x-rays matched the body found in Arches National Park much more closely.

Still, authorities needed DNA to confirm the match, and that wasn’t easy. Peay had been adopted at 11 months, and a judge declined to unseal his original birth certificate.

Police finally received that document — and the boy’s adoption records — in 2022, but found he had no surviving direct family members.

“Through further genealogical searching, detectives were eventually able to locate a maternal uncle and obtain swabs for DNA testing. This DNA was submitted to the National Missing and Unidentified Persons System,” Provo police announced Wednesday.

Once that had been obtained, investigators requested exhumation of John Doe’s body to obtain a DNA sample. Before getting that far, though, they learned that investigators in another county had obtained a sample from John Doe to compare with a case they were investigating. Those detectives had sent the sample to the National Missing and Unidentified Persons System, where it was forgotten until NMUPS notified Provo detectives they had a match for the maternal uncle.

“The DNA match confirmed the remains in Grand County were indeed Provo’s missing person,” Provo police said.