Banka: Police on Wednesday claimed that the three sisters found murdered at a village under Kotoriya block in Banka district on Tuesday had been killed because their mother had a relationship with a relative.

Banka superintendent of police Chandan Kushwaha said the cops suspect that the mother of the three minor girls was in a relationship with an uncle of hers.

"The lady (mother of the girls) also alleged that the family members including her aunt had threatened to eliminate her family," SP Kushwaha said.

He said that police also have some evidence that suggest that the illicit relation had sparked the murder of the girls.

The cops registered an FIR on the basis of the mother's complaint, in which eight persons were named as accused.

All the eight persons are family members of the aunt that the mother of the girls has named.

The police have already arrested the aunt and her son.

"All the other accused have been absconding and we hope they would be arrested soon," SP Kushwaha said on Wednesday.

Asked if the sisters were raped before their murder, the SP said the autopsy report was expected by Wednesday evening and it would prove whether the sisters - whose bodies were found partially undressed - had been raped.