Jason Mark Carter, 39, was declared incompetent to stand trial for the March 27, 2006, killing of his mother, Debra Ann Perkins, and stepfather, Kevin Perkins. He had been committed involuntarily to the mental health facility in Richland County, S.C., nearly eight years ago and escaped Thursday.
The Oconee County Sheriff's Office said in a statement on its website it had learned from the state Law Enforcement Division that Carter was captured by the Tennessee Highway Patrol at a motel in Williamson County in central Tennessee.
Mental health officials said he was captured without incident, ABC News reported.
The Sheriff's Office said Carter stole a white 1991 Chevy van in making his escape, CNN reported.
The Perkins' bodies were found wrapped in plastic in the basement of their Seneca home. Carter was in the room with his alleged victims at the time, the sheriff's office said.
Carter's attorney said his client had no recollection of the crime.