Complex sentence: On April 26,2002,19 year old Robert Steinhauser, a recently expelled student, brang two firearms to school and moved from classroom to classroom shooting teachers, and altogether killed 13 teachers and 2 students.
Split into simpler sentences: On April 26,2002,19 year old Robert Steinhauser, a recently expelled student, opened fire on teachers. He moved from room to room shooting teachers, and killed 13 teachers and 2 students.