MUZAFFARNAGAR, India — Prime Minister Narendra Modi’s new junior minister for agriculture, Sanjeev Balyan, is a first-time officeholder famous for precisely one thing: After two Hindu men were killed in an altercation with Muslims in his district last summer, he rallied crowds of angry young men from his caste, urging them to protect their own kind.

At the time, the police listed Dr. Balyan, a veterinarian, as one of 14 politicians who addressed a crowd that was armed with bamboo clubs and sticks. Their report summarizes the politicians’ message in blunt terms. “Wherever we will find people belonging to the Muslim community, by killing them, we will get our revenge,” the report says.

A week later, mobs of armed Hindu men descended on local villages, leaving around 60 people, mostly Muslims, dead and prompting tens of thousands of Muslims to flee their homes. Dr. Balyan, who had been jailed before the violence, was charged with incitement.

It was an echo of the episode that has haunted Mr. Modi’s political career for more than a decade. In 2002, not long after Mr. Modi had taken office as chief minister of Gujarat, riots broke out after Hindu pilgrims burned to death in a train. Some Hindus blamed Muslims for setting the blaze, and weeks of bloodletting followed. More than 1,200 people died, most of them Muslims. Mr. Modi, who has close ties to right-wing Hindu organizations, was long blamed for failing to stop the killing.