DANTAL, India — For generations, folk musicians have camped out on a dusty cattle range in the northern Indian state of Rajasthan. Mostly Muslims, they earn their keep by performing for Hindus who live in sturdy huts built of stone.

So it came as no surprise when Aamad Khan, a poor singer with deep-set eyes, was summoned to a nearby temple one night to play his harmonium, an air-driven organ. He was told to use his music to inspire the Hindu goddess Durga to enter the body of a local faith healer who happened to smell of alcohol that September evening.

The song would be Mr. Khan’s last.

Around 10:30 p.m., Mr. Khan’s limp body was taken to a hospital, a stripe of blood congealing below one ear. Eventually, the faith healer, Ramesh Suthar, confessed to killing him, saying he had murdered Mr. Khan in a drunken rage, smashing his head against a cement floor.