The boy was missing from his house at Kundara near here, since Monday.
His fully-burnt body was found at a compound adjacent to the house yesterday, the police said.
The story of the gruesome killing unravelled when police questioned the boy's mother, who had some burn injuries on her hands, out of suspicion.
The 44-year-old woman confessed that there was an argument between her and the boy over some property dispute with the husband's family and in a fit of anger she killed him by setting him ablaze, the police said.
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