A man who was using the identity of an 8-year-old boy who died in a Texas car crash in 1945 when he killed himself in 2002 was identified as a 75-year-old Ohio man who vanished in 1965, federal marshals revealed Thursday.

Officials said Robert Ivan Nichols was living under the name Joseph Chandler III for the better part of two decades when he committed suicide in his Eastlake apartment on June 30, 2002. He had been dead for a week when police found his body and were baffled to learn that Chandler was actually a boy from Buffalo who died decades earlier.

An investigation into the man’s true identity went cold until 2014 when the U.S. Marshal’s Office reopened the case with the assistance of Identifiers International, Fox 8 Cleveland reported

During this new investigation, authorities learned that Nichols was treated for colon cancer in a Cleveland-area hospital in 2000. It’s unclear if Nichols used his real name for the procedure, however, marshals were able to track down Nichols’ son to get a DNA sample from him.

The DNA sample matched the one authorities obtained from the hospital.

"This has put to rest a mystery within our family, what happened to him, so to speak," Phil Nichols said of his father, according to Fox 8. "I hold no animosity. I always hoped he'd had a happy life out there."

Robert Nichols, a Navy sailor who was awarded the Purple Heart after being wounded in World War II, was reported missing in 1965 after mailing his son a penny from Napa, Calif. A year earlier he had left his family, telling his wife at the time, “In due time, you’ll know why.”

U.S. Marshal Peter Elliot said on Thursday that Robert Nichols appears to have stolen the boy’s identity in 1978 to apply for a Social Security card in South Dakota.

It’s unclear why Nichols impersonated the dead child, however, his son said his father’s disappearance in 1965 didn’t surprise him.

“He was a loner,” the son said.

Elliot said he believes Nichols ran away to avoid being caught for something he did, the Cleveland Plain Dealer reported.

"He was a decorated war veteran,” the marshal said. “He had a wife and three boys. He had a good life, and he walked away from it all.''

The newspaper reported that over the years there have been rumors about Nichols’ true identity including whether or not he could possibly be the “Zodiac Killer,” who terrorized the Bay Area in the 1960s and 1970s by slaying five people and claiming in letters to newspapers to have killed dozens more. The case is unsolved.

Elliot said Thursday that he couldn't say for sure if Nichols is the “Zodiac Killer” or not and that he Nichols can’t be ruled out as he spent unspecified amounts of time in northern California during that period, according to the paper.