Klamath Falls, Ore.– A Klamath County jury found a Fort Klamath man guilty of sexually abusing his own children. 58-year old Efran Mandoza Valencia was convicted of six charges of first degree sex abuse. Sentencing is next week. Valencia sexually abused two of his children over the course of about six years. They’re adults now, but recently came forward because of concerns that their father had access to other children and were afraid he might abuse them.