SWANG GULGULIA DHOURA, India — For many years, under a tall, spreading neem tree in the middle of this settlement, the village headman has adjudicated disputes between his neighbors, doling out tongue-lashings and occasional penalties.

This, the local police believe, is what happened here a week ago. It began with an ordinary case of bad behavior: A young man crept into a hut after dark and groped Suguna Devi, a married woman and the daughter of the village’s headman, before her shouts woke the village and he fled.

The next day, villagers waited to see what punishment the headman would impose on the assailant — until midafternoon, when they said they saw Ms. Devi’s husband drag the young man’s 13-year-old sister from her father’s hut and into the woods, where he raped her. The worst thing, said the girl’s father, was that no one did anything to stop it.

“My wife wept, but nobody listened,” said the father, Munna Pasi, 62. “My daughter said, ‘Save me, save me,’ but nobody listened. All these people became blind when he was dragging my daughter away.”