A 14-year-old boy on Monday allegedly stabbed and injured his grandparents and aunt with a machete before being overpowered by neighbours as he suspected they had driven father to suicide last year. The incident occurred at a house in Chetla Road where the victims lived.

The boy, a Class VII student of St Helena school, has been arrested and would be produced before a juvenile court on Tuesday.

His grandfather, Anil Ghosh (75), grandmother Chayanika Ghosh (68) and aunt Baisakhi Saha (45) were rushed to SSKM hospital, where two of them were given first aid and discharged.

In a statement to police later, the boy confessed to the crime and said he wanted revenge.

According to police, the boy, who lives with his mother Sanchita in Janbazar, took Rs 150 from his mother on Monday morning on the pretext of paying his school fees. After the school, he went to Kalighat, about 7 km from his residence, and bought a machete. He then headed straight to his grandfather’s home on 37/2 Chetla Road, the machete lying in his school bag.

“His grandmother offered him fish and rice for lunch. As he finished his lunch, he saw his aunt Baishakhi entering the house. He could not control his rage and suddenly took out the machete from his school bag before attacking his aunt,” said an officer of the detective department.

Chayanika rushed to her rescue but was also hit by the boy. Anil, who was in the bathroom, soon came out hearing the screams but he too was attacked, the police said, adding the boy hit them with the machete indiscriminately.

Family members then raised an alarm after which neighbours rushed in and overpowered the 14-year-old before calling the police.

During his interrogation, the boy said he suspected his father Ranapratap Ghosh was driven to suicide on September 4 last by his grandparents and aunt.

“The boy’s father and grandfather regularly fought over the ownership of a fast-food shop their family ran. The boy’s father left Chetla home and started living in a rented house on Rani Shankari Lane near Bhawanipore,” added the officer.

He said the boy appeared to be having no psychological problem and was calm after the incident.