A Pennsylvania school bus aide is charged with stabbing a nurse at the school and holding a 14-year-old student hostage at knifepoint in a bizarre burst of violence. Police said the incident unfolded shortly after 9 a.m. Wednesday during morning drop-off at the Watson Institute, a school for special-needs students in Allegheny County. Rochelle Pinkle, an aide at the Sewickley school, allegedly stabbed the school nurse twice in the back, then grabbed the student and led him at knifepoint back inside her bus, WTAE-TV said. She released the teen after police arrived but struggled with the cops and had to...