Baylor County Sheriff Bob Elliot says the case will be treated as a homicide pending additional investigation and an autopsy report.
The man was identified as 60 year old Danny Charles Earnest.
Elliot says Earnest's body was found by a landowner Thursday morning and was a couple of hundred feet from his vehicle, a Dodge van.
The key of the van was in the ignition.
Elliot says there did not appear to be any evidence of trauma or foul play, but until more evidence is obtained they will treat it as a homicide.
Texas Rangers are assisting in the investigation.
Earnest was reported missing September 21. Elliot said he had apparently been in route from Plano to Lubbock. He said Earnest may have had medical problems and was last seen at United Regional Hospital for a medical issue, but declined treatment.