A Class 12 student opposed to his brother's relationship with a girl has been arrested for gunning down the girl's mother in the Indian capital, the police said Monday.The 17-year-old was arrested from Kundli area Sunday for killing Rita Dube, who was in her late 30s, last week following a heated argument at her house in Narela, a police offical said.

Rita, her husband Brijesh, their three daughters and two sons had moved to New Delhi some time back from Gorakhpur in Uttar Pradesh. The Dubes were known to the family of the accused.

'Rita's elder daughter was in love with the accused's elder brother Atul. They wanted to marry. Rita and her husband had no objections. But Atul's mother and brother were strictly opposed to it,' said Deputy Commissioner of Police (Outer Delhi) Sagar Preet Hooda.

'Last week the accused and Rita had an argument over the issue. The accused pulled out a country-made gun and fired at Rita from point blank range. She died on the spot,' he added. Police said they have recovered the murder weapon from the accused.