Police released the results on Wednesday, saying the coroner has confirmed the 17-year-old's identity. Investigators believe 17-year-old Jose Campos shot Rios, then set his body on fire.
Campos and his girlfriend, 17-year-old Felicia Sharp, are believed to be on the run.
Campos' mother and stepfather were taken into custody as accessories, but were released last week because charges have not yet been filed.