Amador County District Attorney Todd Riebe has filed first degree murder charges against William Garrett Oaks, 46.  Oaks, an inmate at Mule Creek State Prison in Ione, is accused of strangling his cellmate, Lee B. Merrill, 59, who was found dead in the prison cell Oaks and Merrill shared on September 29. According to Riebe, the murder occurred about 11 p.m. on September 28, about 12 hours after Oaks was assigned to Merrill’s cell. The coroner’s report said Merrill died of asphyxiation. Oaks has a long criminal history of drug and theft convictions, including two felony convictions in Sonoma County for petty theft with a prior conviction and grand theft. Merrill, serving a 16-year sentence for child molestation, was discovered in his cell by prison staff about 6:30 a.m. the morning of Sept. 29 and pronounced dead 30 minutes later at the prison’s medical center. Oaks is facing 25 years to life in state prison if convicted.