What began as a playful scuffle between two boys at a Shaanxi secondary school spiralled into tragedy on Tuesday after one of them was slashed to death with a knife, mainland media reported . The two ninth grade students, surnamed Ma and Lu, were “play fighting” during recess at the Yanchuan county school on Tuesday afternoon. Ma accidently broke Lu’s nose in the exchange and this sparked a fight. Classmates pulled the two apart. During a class later that day, Lu pulled out a small knife, walked over to Ma's desk and slashed his throat. The boy was sent to Fuxian Hosptial, where he died shortly afterwards. Ma has been detained by local police. The county's education office is waiting for results from a police investigation to see if other students and teachers had been involved in the incident.