WASHINGTON : Twenty people, including 19 students, were wounded - four seriously - during a stabbing spree early Wednesday at a high school in Murrysville, Pennsylvania, the town’s police chief said.An unidentified student entered the Franklin Regional High School shortly before the start of the school day and began stabbing students. The stabbings happened in numerous classes throughout the building before classes had begun. Not all of the 20 injuries were stabbings but some were cuts and scrapes.According to the town authorities, 4 people have been flown to a hospital, and Forbes Regional Hospital in Monroeville is treating 8 others. Police and emergency medical personnel are at the school and three medical helicopters are present, ready to take people to the hospital. The student is currently in police custody and he is being interviewed by Murrysville police. The school is considered secure.