Authorities in Twin Falls County say a father and his son are being held on separate charges of sexual assault.

They say 43-year-old Franklin Ward Osterhoudt and his 20-year-old son, Franklin Scott Osterhoudt, are being held early Saturday at the county jail.

The elder Osterhoudt faces five counts of lewd conduct with a minor under 16, one count of incest and one count of rape stemming from allegations involving a family member between 2002 and 2006. He was arrested in Nogales, Ariz., and has pleaded not guilty.

His son faces two counts of statutory rape for two incidents involving a 15-year-old girl.

Both men from Buhl face up to life in prison and fines if convicted.

County Prosecuting Attorney Grant Loebs says such coincidences are "not frequent."