JOLIET, Ill. (AP) — Human remains discovered in 1974 near a northeastern Illinois creek have been identified through forensic DNA testing as a suburban Chicago man who vanished in the early 1970s, officials said.

The skeletal remains are those of Donald M. Rozek of Harvey, Illinois, and Rozek’s cause of death remains undetermined, the Will County Coroner’s Office announced Wednesday.

The coroner’s office and the Will County Sheriff’s Office worked with Othram Inc. — a private laboratory that conducts advanced forensic DNA testing — to identify Rozek’s remains, The (Joliet) Herald-News reported.

Hunters found the skeletal remains in November 1974 near a Will County creek bed northeast of Interstate 55 and Route 6. The remains were eventually buried but were exhumed in December 1993 for more analysis by the sheriff’s office. The man’s identity remained unknown, but the coroner’s office began working on the case through a cold case unit formed in 2009.

Working with the coroner’s office, Othram Inc. developed a genetic profile last year that was submitted to FamilyTree DNA, the coroner’s office said. Genealogists then narrowed down family leads, prompting investigators to interview several people from Washington, Hawaii, Georgia and Florida.

After additional DNA profiling and genealogy work, Othram narrowed the search to an Illinois resident who was a possible nephew of the unidentified man. Subsequent testing determined that he and the man were in fact nephew and uncle.

The nephew told investigators he had an uncle who vanished in 1971 or 1972 and was never seen again, according to the coroner’s office, which said Rozek is believed to have been an Army veteran.

The case remains under investigation, but Deputy Coroner Joseph Piper said Rozek would have been between the ages of 26 and 30 when he vanished.