The incident occurred at Karahkol village of Deoria, 475 km from state capital Lucknow. Police have so far arrested two people in this connection and raids are being conducted at several places to apprehend other culprits.
Police said a girl named Manju was in love with a boy named Ranjit of the same village. The boy's family opposed the relationship, and the matter was taken to the panchayat. At the panchayat meeting, Manju's mother pleaded that since the two loved each other, they should be allowed to marry.
Incensed by the proposal, Jai Hind, Ranjit's father, and members of his family assaulted Manju's mother Gyanwati and rained blows and kicks on her.
Manju rushed to help her mother as she was being attacked, and members of Ranjit's family doused her with kerosene and set her on fire.
Police reached the spot on being informed of the incident. By that time, Manju, who was taken to a nearby medical facility, had died of burn injuries.
A first information report (FIR) was filed based on the sequence of events narrated by Gyanwati, the girl's mother. Seven people have been charged with the crime, and two of them have been arrested. Policemen said the absconding five would soon be nabbed.