Forensic DNA sleuths may be close to finding the truth behind one of the oldest unsolved missing persons cases in U.S. history.
The breakthrough will be too late for Marvin A. Clark, who vanished during a trip to Portland on Halloween weekend 1926 and would be more than 160 years old were he alive today, according to a report Wednesday by The Associated Press.
The case has been cold for 90 years but investigators have used modern DNA technology and several online databases to find three great-great-grandchildren on Clark's paternal side.
They are now working to locate someone on his mother's side to shore up the results.
Clark was a "well-known" Tigard, Ore., resident who went missing while traveling by bus to visit his daughter in Portland on Oct. 30, 1926, according to The Oregonian newspaper at the time. He was reportedly between 60 and 75 years old.
A frantic search and a $100 reward — more than $1,300 in today's money — returned no results, despite police across the Northwest being told to look out for Clark, who was partially paralyzed and had a "hanging gait."
Then 60 years later, on May 10, 1986 loggers in Portland discovered a skeleton alongside some unusual belongings: a 1888 V nickel, a 1919 penny, a pocket watch, leather shoes, wire-rimmed glasses, a Fraternal Order of Eagles pocket knife, and four tokens with the inscription "D&P," believed to be tavern tokens awarded in card games and used to buy alcohol.
Police also found a corroded revolver, and an expended .32-caliber bullet. A single shot had entered the skull at the temple. Medical examiners, who said at the time said it was the oldest case they ever had, ruled the unknown man's death a suicide.
The case went cold again. That was until Dr. Nici Vance, of the Oregon state medical examiner's office, made the recent breakthrough when she entered Clark's name into the National Missing and Unidentified Persons System (NamUs), a free system used by officials to try to put names to unidentified corpses.
NBC News' Alexander Smith contributed to this report.