Investigators say 38-year-old Juan Jimenez Tovar was discovered west of Vega last week. He was not initially identified, but authorities later heard from the man's 15-year-old son in Washington state. The teen said the man his father was riding with had called to say Tovar was left at a rest stop after becoming sick or unconscious.
Sheriff David Medlin told the Amarillo Globe-News that the man "told the son they were going to call 911, which they didn't."
Officials aren't sure when Tovar died, but a preliminary autopsy showed he likely died of natural causes.
Medlin said authorities don't know with whom Tovar, who was undocumented, was riding or where he was going.