Riley's son, Richard Floyd Thomas, told authorities that he dropped his father off at a bus station in Lufkin, Texas on January 31, 2000. Riley was scheduled to travel to Houston, Texas and transfer buses in Port Arthur, Texas. He never arrived as planned and has not been heard from again. His ex-daughter-in-law reported him as a missing person on April 6, 2000, more than two months after he was last seen. He may have traveled to Louisiana or Oklahoma.

Richard Thomas moved to Oklahoma around the time of his father's disappearance. He was later convicted of forging his father's name to cash checks on Riley's bank accounts, and is considered a suspect in his father's disappearance. Riley is presumed deceased and foul play is suspected, but his body has never been found. He is a retired correctional officer.