The investigation into an explosion in the washroom of a school in Chhattisgarh revealed that five students, including three girls, orchestrated the blast by planting sodium metal to target a female teacher they are upset with, police said on Tuesday.

A class IV girl student was injured in the explosion which occurred on February 21. Following a thorough investigation and examination of CCTV footage, the police detained four of the five involved students on February 23. The four detained children, all class VIII students, were produced in a juvenile court which sent them to the juvenile home, a police officer said.