Police arrested a man on charges of murdering his wife's sister on Wednesday night. Police said Saravanan (32), a welder, had an argument with the victim, Kalpana (21), at her house in Kalaignar Karunanidhi Nagar, Thirumullaivoyal, over her relationship with a male colleague. In a fit of rage, Saravanan strangled Kalpana. Neighbours rushed in as she screamed for help. Saravanan fled, but was apprehended by a police patrol team nearby.