Two other people were injured when the shell landed in the house's courtyard, Kumar said.
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An Indian mortar shell misfired during an army training session Wednesday, killing a young couple and a neighbor in a nearby village. (Fox News)
The army did not immediately comment on the incident.
The village is located 65 miles south of Patna, the state capital, near the army firing range.
Other accidents have been reported near the military site over the past year.
A civilian was killed near the firing range last year when a shell exploded as he was trying to remove brass from it to sell, media reports said. In another incident in December, at least 10 people were injured while they collected wood near the firing range for use in cooking and to sell.