Two miles down the road from the white marble walls of the fabled Taj Mahal, a heavyset man crouches in the dirt of a cow shed and explains how the future of India belongs to him. Digvijay Nath Tiwari is commander of a vigilante group that claims 5,000 members in the northern city of Agra, and which cultivates informants, swarms shop owners, ambushes trucks at night and metes out extra-judicial violence, all for one cause: protecting the holy cow, an animal held sacred by Hindu beliefs. Across the country, hardline Hindu groups have made headlines after being captured on video insulting and beating men they accuse of involvement in cow slaughter. "Retaliation is important at times," said Tiwari, as he sat with 17 men squeezed around a straw mat on the shed floor. His cell phone contained photographs of stick-wielding men rushing to the aid of fallen cattle.

Once at the helm, however, he has focussed on more pragmatic and inclusive economic issues: spurring growth and creating enough jobs for a rapidly expanding workforce.

These initiatives could be derailed by a narrower, Hindu nationalist agenda aimed at protecting symbols made sacrosanct by religious texts and countering a perceived threat of foreign influences.

In a speech on Saturday night in New Delhi, Modi lashed out at the cow protectors.

"I feel so angry at times. Some people who are engaged in anti-social activities for the whole night wear the mask of 'gau rakshaks' in the day," he said.

A senior aide to Modi, who is approaching the halfway mark of his five-year tenure, said at the end of July that while the leader is aware of the social and economic implications, "we cannot do much to stop cow protection forces ... cow protection is integral to our core support base."

DALITS FEEL UNDER SIEGE

The violence of cow vigilante groups this year, some of it caught in disturbing videos on the Internet, has unsettled minority groups.

One clip from the western state of Gujarat shows four men, shirtless, tied to a bumper being whipped with rods. The victims were Dalits, or Indians at the bottom of the caste hierarchy who traditionally take away cow carcasses which can then be used for leather.

In another, from the northern state of Haryana, two people are made to sit on the road and eat a concoction including cow dung. They were reportedly Muslims, and the footage was taken during Ramadan, the Islamic month of fasting.

While the BJP does not bank on the support of many Muslims, it does want to secure the votes of the Dalits, a caste formerly known as untouchables.

Together, the two groups account for about 30 percent of India's population, a major consideration with important state elections due next year and a national ballot set for 2019.

Chandra Bhan Prasad, a prominent Dalit writer and adviser to the Dalit Indian Chamber of Commerce and Industry, compared the violence to that of Ku Klux Klan racism in the United States.

"It's like India's version of KKK – the past was great so long as these blacks were under our thumb, society was beautiful. So, how to control these Dalits?"

"COW NOT JUST AN ANIMAL"

The Rashtriya Swayamsevak Sangh (RSS), the nation's umbrella right-wing Hindu organisation which helped create the BJP, does not appear willing to tackle cow protection forces, blaming outlaws for causing the trouble.

"The cow is not just an animal. We have an emotional and religious attachment to it and we want to make it the centre of our economic activity," said a senior RSS leader in New Delhi, who asked not to be named so he could speak more frankly.

"Vigilantes are instructed to follow the rules and they are a disciplined force. We admire their work."