Tension prevailed at Kurayur near Kalligudi in Madurai district after one of the three victims, who were stoned in their sleep on Friday night, succumbed on Sunday afternoon.
A heavy posse of police was deployed at the village to prevent any untoward incident.
R. Vellai (50), a Dalit, who had sustained head injury in the attack, died at the Government Rajaji Hospital (GRH). Based on a complaint lodged by Tiruvettai (83), who was also injured along with A. Chandrasekar (27) in the attack by an unidentified gang at around 11 p.m., the Kalligudi police had registered a case for attempt to murder and under the provisions of Scheduled Castes and Scheduled Tribes (Prevention of Atrocities) Act, 1989.
Four persons — K. Kanagarpandi (19), M. Pandi Karuppan, K. Pandikaruppan and a minor boy — were picked up by the police.
The police said that the accused, all caste Hindus, had randomly attacked with iron rods, clubs and stones those sleeping in the open auditorium in the village. The attack is suspected to be a revenge on an assault of a person belonging to their group during a cultural programme held in the village in November 2014.