Human remains found in a shallow grave in Ohio in 1991 are those of a missing Columbus man, officials said Tuesday, marking another cold case homicide broken open by advancements in DNA and genealogical research.

The man was Robert Mullins, 21, who had vanished two or three years earlier, state prosecutors and Pickaway County sheriff’s deputies said.

“Thirty-one Christmases have come and gone, and I was thinking about the headstone with no name on it,” Ohio Attorney General Dave Yost told reporters.

“We’re all going to die at some point. That’s the only thing that’s certain about our lives on this Earth. But what a tragedy to die unknown, to not have a name to put on the memorial. Today that circle closes.”

A pair of hunters stumbled upon Mullins’ skeleton north of State Route 56 just west of State Route 159 in Pickaway County on Nov. 1, 1991, state and local officials said.

Investigators originally believed the remains were those of a long-dead Native American woman, about 25, because the person was no taller than 5-foot-4 and because of the region’s connection to indigenous communities.

Eventually, anthropologists determined that the remains hadn’t been in the ground for more than three years. And it wasn’t until 2012 when University of North Texas researchers tested the DNA and determined that the body was that of a male with Indian ancestry, officials said.

In 2021, Pickaway County Sheriff’s Lt. Jonathan Strawser and Dr. John Ellis, the coroner, teamed up, seeking to match their John Doe to available public databases of DNA in hope of building the man’s family tree, officials said.

They brought in forensic genetic genealogy researchers from AdvanceDNA, who ran John Doe’s DNA and matched it to that of 4,000 people in the U.S. and England — before narrowing his tree down to a father from Virginia and a mother with ties to England and India.

“After Robert’s sudden disappearance, his family looked for him, especially his late mother,” said Amanda Reno, AdvanceDNA’s director of genetic and forensic case management.

“His family explained his absence had been a great source of pain for their family. He was loved, and he was missed.”

Sheriff’s investigators said they hope to someday find a suspect in Mullins’ murder.

“Now the detectives have the new information, [and] that’s going to allow them to do what they do best: hit the streets, put the pieces together and look at the final days of Mr. Mullins’ life and find out who did this to him,” Yost said.

Strawser said he is grateful for help from all of Mullins’ relatives, who took a keen interest in this case even though the victim was a stranger to them.

“We would also like to thank Robert’s genetic relative matches who volunteered their time [and] family information,” Strawser said. “Robert was a distant cousin to them. Despite being somebody they had never met, each of these relatives played a key role in bringing him home to his family.”

Strawser said he is cautiously optimistic about finding Mullins’ killer, knowing how far behind investigators are.

The man’s body had been so decomposed in 1991 that detectives don’t even know how he died.

Investigators still haven’t found a missing persons report for Mullins in Columbus police files. The victim’s parents have since died.

Detectives are “appealing to the public for help in learning more about Robert, possibly about who he hung out with,” Strawser said Wednesday.

“There’s no physical evidence in the case. Nothing at all. The only evidence we’re going to have is the public’s help in getting us people to talk to. Are we 100% certain we’re going to find the killer? Absolutely not. But we’re going to try out best.”

The practice of matching genetic material of victims and perpetrators to the millions of people who take do-it-yourself home DNA tests has proven to be a valuable new asset to police.

Last week, Philadelphia police identified 4-year-old Joseph Augustus Zarelli as the “Boy in the Box” who was found beaten to death in 1957 and had gone nameless until recently.

And most famously, DNA and genealogy led police to the Golden State Killer, Joseph James DeAngelo, who terrorized California in the 1970s and ’80s but wasn’t arrested until 2018.

DeAngelo was sentenced to multiple life terms for 13 murders and 13 rape-related charges; he has been connected to many more sexual assaults.

This article was originally published on NBCNews.com