The FBI says some ransom notes in the disappearance of Nancy Guthrie have been ruled extortion while other notes remain under active investigation.Investigators are tracing email origins through proxy servers, have detained and released multiple people of interest, and say a person who tampered with a doorbell camera appeared inexperienced.Volunteers recently searched desert and brush near the Arizona-Mexico border, and authorities continue to take tips seriously as they examine surveillance footage of a masked man and blood found at Guthrie’s home.