The 11-year-old class 6 student of St Dominique Savio School was slapped by the teacher, who then took away her answer script and asked the girl to stand outside the classroom, according to a complaint filed by the victim's parents against the teacher and school headmaster.

The girl then went up to the roof and took the extreme step, the complaint said.

"The teacher and the school principal have been detained. They are being questioned," said a police officer.