Devi temple priest Budh vilas Tiwari lodged a police complaint at the Sikandra police station on Monday after his six-year-old daughter Subiksha went missing from their home.
During the investigation, his second wife Archna Tiwari, 22, broke down and confessed to having buried Subiksha in the temple.
Archna later guided the cops to the spot in the temple premises where the girl was buried.
Archna was worried about the future of her one and a half-year-old son who she thought would not get his due as the family's meagre earnings would be spent on Subiksha's education and later marriage, police said.
An angry mob enraged over the incident assaulted Archna soon after her confession. Police had to use batons to disperse the crowd.