A former northern Kentucky homebuilder and his father pleaded guilty on Monday to charges that they pressured the builder's sister to change her testimony to try to get him a lighter sentence on a fraud conviction. Bill Erpenbeck and his father Tony both pleaded guilty in U-S District Court in Cincinnati to one charge of conspiracy to obstruct an official proceeding. The charge carries a maximum sentence of up to 30 years in prison. The Erpenbecks pleaded innocent to the charges last month. The Erpenbeck Company constructed houses and condominiums in Kentucky and Ohio defrauded ten banks and at least 260 home buyers out of $34 million. Bill Erpenbeck is set to be sentenced on both convictions this Thursday. His father's sentencing has not yet been scheduled.