The skeleton was found on federal land, so it technically fell under U.S. Army Corps of Engineers' control. But five Native American nations claimed that the "Ancient One” was in fact Native American and should be repatriated under NAGPRA. This assertion was controversial until a 2015 study showed that Kennewick Man was in fact Native American. Though the DNA evidence from this study didn't link him to a particular nation, it showed that his genome was more closely related to modern Native Americans than any other modern human in existence.
Click here to read the entire story at Smithsonian.com.