SCRANTON, Pa. (AP) -- A northeastern Pennsylvania prison guard charged with sexually assaulting five female inmates has been fired. Lackawanna County prison officials said 49-year-old Joe Black of Dickson City was let go Friday after a hearing. Earlier this month, he was charged with assaulting the women at the county prison between 2002 and 2011. A grand jury found that Black frequently volunteered to oversee female inmates -- a job typically done by female guards. The investigation began when a former Lackawanna inmate told investigators she had been sexually assaulted by Black, but only made the report after she had been moved to a federal prison. His attorney says Black is innocent. The investigation began more than two years ago. Black had been suspended with pay until his firing.