(Tigard, OR)  --  A school bus driver for the Tigard-Tualatin School District is under indictment after being accused of sexually abusing a special-needs student.  Authorities say 60-year-old Mario Mendez Ruiz of Hillsboro committed the abuse in late March after dropping off all other children from the bus.  Ruiz is facing charges of second-degree kidnapping, third-degree sexual abuse and first-degree criminal mistreatment.  Investigators say Ruiz gave the girl money and instructed her not to tell anyone.