OKLAHOMA CITY (AP) — Oklahoma officials say a Thailand native whose body was found along the side of a state highway in July died from a methamphetamine overdose.

The Oklahoma State Bureau of Investigation reported Friday that 41-year-old Thanakrit Thuetong died from acute methamphetamine toxicity. The manner of death was ruled accidental.

Thuetong's body was found in July along the side of a highway in Seminole County, less than a mile from Interstate 40. Investigators believe Thuetong had been living in Florida and was driving along I-40 to visit relatives in California.

OSBI agents have said Thuetong parked his car in the parking lot of a Seminole County convenience store. Surveillance video showed him inside the store with a black backpack, then walking past his car and along the highway.