The discovery of a human jawbone submerged in a remote stretch of river running through central Iowa triggered a police investigation - and after weeks of digging, investigators have returned with a surprising answer.
Workers stumbled across the jawbone in early August while conducting a wildlife survey for the county, the Marshall County Sheriff's Office said in a Sept. 21 release.
Investigators went to the site and searched, uncovering more bones initially believed to be human, but later determined to be animal.
The jawbone was a mystery, a lone piece of an unknown person. It could tell deputies nothing about how it got there, who it belonged to and how they died.
Whoever they were, their death wasn't recent, the sheriff's office said, as the jawbone was "several years old."
It was actually ancient, investigators would soon learn.
The county passed the jaw along to the State Medical Examiner's Office, which examined it, then handed it over to the Office of the State Archaeologist.
The jawbone is more than a piece of evidence, investigators found. It's a piece of ancient history, the remains of a man who lived and died thousands of years ago.
"The mandible was determined likely to belong to a prehistoric Native American, middle to older age male," the sheriff's office said.
Investigators didn't provide a specific time frame in which the man may have lived and died, but "additional historical research is expected," the release said.
Evidence collected in recent years shows that humans began inhabiting the Americas at least 13,000 years ago - a point when experts say "ancient populations expanded rapidly" across the continents, Science reported in a 2018 article.
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