A human skull found earlier this week in Kentucky is up to 3,000 years old. The remains are thought to belong to a person indigenous to the eastern United States, local ABC affiliate WKYT reported Friday.

A farm worker discovered the skull in a 12-foot-deep sinkhole near Frankfort, the state capital. Franklin County officials later confirmed the skull was of a Native American person dating back between 1,000 and 3,000 years, WKYT said.

William Harrod, the coroner in Franklin County, said his office had suspended its investigation and would work with the Kentucky Heritage Council and the State Historical Preservation Office to properly rebury the skull.

The thousands-year-old remains are relatively young for a human fossil. In Ethiopia earlier this year, paleoanthropologists said they had discovered a 2.8-million-year-old jawbone -- making it the oldest fossil in the human ancestral line ever found by more than 400,000 years.

The ancient mandible was unearthed just 40 miles away from the grounds where scientists in 1974 found “Lucy,” a 3.2-million-year-old hominid.

In May, another research team found upper and lower jaws that included teeth, which are believed to have belonged to a new species of hominin, the subset of hominids that includes modern humans and our direct ancestors. The fossils are thought to date back 3 million to 4 million years ago, meaning ancestors to modern humans may have been more diverse than initially understood.

A younger skull -- just 430,000 years old -- was recently found at an archeological site in northern Spain. The site is located deep underground in a cave and holds the skeletal remains of at least 28 early humans. Scientists discovered lethal wounds on the fossilized skull, proving that deadly interpersonal violence is an "ancient human behavior," the scientists said in a study, published in the journal PLOS One.