Two children were burnt alive while their parents were reported to be critical when the house of a Dalit family in Haryana's Faridabad district was set on fire on Tuesday, police said.
The house of Jitender in Sunped village near Ballabgarh was set on fire by unidentified people after dousing it with petrol.
Villagers Dushyant and Vipin said that Jitender, his wife Rekha, four-year-old son Vaibhav and eight-month-old daughter Dibbo were rushed to Safdarjung hospital in Delhi.
Police said that Vaibhav and Dibbo succumbed to burn injuries.
Inter-caste rivalry is suspected to be the reason behind the gruesome incident.
Following tension in the village, all shops were closed and heavy police force was deployed in the area.
Deputy commissioner of Police (Ballabgarh) Bhupinder Singh said that the situation in the area was tense but under control.
Police said that an incident that took place on October 5, 2014, when three people were killed in clashes between two groups of the village, may have led to Tuesday's arson.
Police said that 19 people were booked for triple murder including three members of Jitender's family after the 2014 violence.
