The incident occurred at Tulshihatta village under Harishchandrapur police station after the shopkeeper 'found' the girl stealing the watermelon.
As he started beating up the girl, he was joined by a group of men and the girl died on the spot, they said.
Local people then caught two of the accused, including the shopkeeper, beat them up and handed them over to the police.
Both of them were admitted to hospital, they said.
Deccan Herald is on WhatsApp Channels| Join now for Breaking News & Editor's Picks