Authorities say a human bone discovered at a New Mexico reservoir believed to be connected to possible victims of a decades-old sex torture case can't be identified.
The Federal Bureau of Investigation said this week that the Albuquerque office of the medical examiner couldn't determine the identity of the human femur found in 2011.
FBI spokesman Frank Fisher says the bone appears to be of "historical archaeological origin" and has been sent to an FBI lab for more tests.
The FBI and Albuquerque police are looking for any remains of missing victims of David Parker Ray.
Authorities have long believed Ray, who died in 2002 while serving life in prison for sexual torture, buried some of the 40 victims he claimed to have had.
No bodies have ever been found.
Copyright 2013 The Associated Press.