Five members of a family have been burnt alive in Bihar's Purnia district on suspicion of practising 'witchcraft', media reports said.

Late on Sunday night, a 50-strong mob barged into the house of Sita Devi and accused her of practising 'black magic' in Tetgama village.

The woman's son, 16-year-old Sonu Kumar, said the members of the mob thrashed everyone in the family when he managed to escape and take shelter at a relative's house.

"People from the village came with bamboo sticks and beat everyone, calling my mother a 'witch'. They beat up five people, including my mother, father, brother and sister-in-law. The other villagers did not stop them," Sonu told reporters.

All five, including Sonu's parents, were then set ablaze by the mob, and their bodies were hidden under water hyacinth.

Purnia Sub-Divisional Police officer Pankaj Kumar Sharma said Sonu filed a police complaint on Monday.

"Sonu Kumar said his family members were beaten and burned on suspicion of practising 'witchcraft' and their bodies were thrown away. We have recovered the bodies," Sharma said.

According to him, a villager, Ramdev Oraon, had recently lost one of his sons, and another was seriously ill. The villagers blamed Sita Devi for this and set them ablaze.

Stating that two people have been arrested so far, he added, "The incident is serious and none of the people who are involved will be spared," he said.