Principal Ritu Chhabra, 47, was shot at thrice at her chest, stomach and shoulder from a close range with a .32 bore gun by the student in the premises of Swami Vivekanand Public School between 11.30 am and 12 noon. The school is in Thapar Colony of Yamunanagar town, around 110 km from Chandigarh.
Police told IANS that the licensed pistol belonged to his father. During investigation, it came to light that the student stole his father's licensed revolver by breaking the wooden almirah at his home. He took the revolver without the knowledge of his parents, SP Kalia told PTI.
"School staff, students and teachers caught the accused while he was trying to escape and handed him over to police," a senior police officer told IANS.
Prima facie investigations by the police suggest that the boy came on a motorcycle accompanied by at least one of his friends and headed straight to the principal's office.
More than five rounds were fired, triggering panic and horror among the school staff, teachers and students.
The 18 year old commerce student had been rusticated as he had low attendance for picking fights with other students.
The critically injured principal was rushed to hospital where she succumbed to her injuries.
The police have registered a case against the student. His father is also likely to be booked under the Arms Act, police told IANS.
(With inputs from PTI and IANS)