Tired of watching his mother being regularly bashed up by her lover, a Class 10 student from Antop Hill stabbed the 60-year-old man to death on Monday night.
The victim, Manohar Naidu (60), who was unemployed, was married to four women but was staying with the boy's mother for the past six years.
Sources said neighbours used to taunt the 15-year-old about his mother's illicit relationship, irritating him even more.
The incident took place on Monday, around 10.30 pm, when Naidu came to his shanty behind the Antop Hill post office after having had too much to drink.
He and the boy's mother got into an argument over his drunken state. The fight soon turned violent, with Naidu then proceeding to beat up the woman mercilessly.
The boy, whose father passed away a few years ago and who has two younger sisters, was enraged as he had seen this happen too often.
According to him, Naidu would regularly come home drunk and beat up his mother.
According to senior police inspector of Antop Hill police station D. Devkar, "There were constant fights between the couple where Naidu would hit her. The boy could not take it anymore and stabbed him in the chest with a chopper. Naidu was rushed to KEM Hospital where he was declared dead. The boy made no attempt to run away after the incident."
Police officials added, “Naidu has one wife in Kuwait, one in his hometown, one in Mumbai and the fourth died a few years ago. He does not seem to have married the boy's mother and had merely being living with her.”
Police officials have sent the boy to the Dongri children's home.