BISARA, India (Reuters) - The murder by a Hindu mob of a Muslim man rumoured to have slaughtered a cow has thrown a spotlight on the hardline, polarising agenda of some followers of Indian Prime Minster Narendra Modi, undermining his promise of development for all.

On a tour of Silicon Valley last month, where he was feted by United States tech gurus and Indian emigres, Mr Modi won a pledge from Microsoft to provide low-cost Internet for 500,000 villages to back his vision of a globally networked "Digital India".

One such village is Bisara, 50km from the capital New Delhi, where a crowd of assailants broke into Mr Mohammed Akhlaq's home last Monday night, beat him to death and dragged his body out into the street.

The local member of Parliament Mahesh Sharma is also Mr Modi's culture minister, and has hit the headlines of late with statements that show a different side to their ruling Hindu nationalist party. In one recent speech, Mr Sharma vowed to cleanse public life "polluted" by Western influences.

Visiting Bisara this week to pay his respects to Mr Akhlaq's family, Mr Sharma said the killing could have been an "accident".

"How can the leader call my husband's murder an accident?" Mr Akhlaq's widow Ikraman, who suffered facial injuries, told Reuters at the family home. "I don't think the minister knows the difference between an accident and murder."

Critics say Mr Sharma's comment implicitly condoned Mr Akhlaq's lynching and pandered to fringe Hindu militants who have recently become active in the district.

Eating beef is a taboo for many Hindus, who make up 80 per cent of India's population of 1.25 billion people, but not for the country's 175 million Muslims.

Communal clashes had never erupted in Bisara, home to 400 landowning Hindu and 35 Muslim families, even when religious riots have broken out in the region. In 2013, 65 people died in sectarian strife around the northern town of Muzaffarnagar.

But an announcement by a Hindu priest over his temple loudspeakers that Mr Akhlaq had butchered a cow and that his wife was cooking beef for dinner brought a sudden end to the village's tradition of tolerance, according to family members and villagers who heard the call.

Within minutes, a mob stormed into Mr Akhlaq's house, vandalised the kitchen in search of beef and beat the 56-year-old blacksmith to death with bricks and stones. His body was dragged out in front of his family.

Mr Akhlaq's youngest son, who suffered severe head injuries, is fighting for his life in a hospital intensive care unit after undergoing two brain operations.

His widow says he was killed for a crime he did not commit. "Even now I can't believe that my Hindu neighbours killed my husband. My neighbours were like my extended family," said Ikraman, who will spend a month in mourning in a room near the bloodstained murder scene.

Local Muslims say Mr Akhlaq's killing was a pre-meditated attack aimed at polarising the village on religious lines by militant Hindu groups loyal to Mr Modi's Bharatiya Janata Party (BJP), which won power in the May 2014 general election.

Mr Sharma and Mr Modi are both members of an umbrella group, the Rashtriya Swayamsevak Sangh (RSS), that is the BJP's ideological parent. The movement propagates an ideology of Hindutva, or Hinduness, which asserts that India is a Hindu nation.

Police have arrested seven Hindu youths over the murder and one paramilitary soldier accused of planning the attack. Investigators are also searching for Hindu activists who spread rumours and online posts stating that Mr Akhlaq had stored 6kg of beef in his refrigerator.

The region holds village council elections next week and Bisara has, in the wake of the killing, become a magnet for campaigning politicians.

One BJP lawmaker accused of instigating the Muzaffarnagar riots came to Bisara on Sunday and warned of a "befitting reply" if the suspects were prosecuted, according to news reports.

Many Indian states, including the country's largest Uttar Pradesh, where Bisara is situated, have banned cow slaughter for more than two decades.

Mr Modi's party has, in states where it rules, clamped down further on eating beef - even though India is the second-largest exporter and fifth biggest consumer in the world. In recent months, government leaders have advocated a national ban on cow slaughter.

Critics say tougher anti-beef laws discriminate against Muslims, Christians and lower-caste Hindus who rely on the cheap meat for protein.

The crackdown has, meanwhile, provided cover for the rise of Hindu vigilante groups.

Such groups attack cattle trucks, track religious conversions in villages and towns, and warn Hindu girls against falling in love with Muslim boys.

Mr Modi has expressed no disapproval towards them. "Those who spread this poison enjoy his (Modi's) patronage," political analyst Pratap Bhanu Mehta wrote in the Indian Express. "This government has set a tone that is threatening, mean-spirited and inimical to freedom."

Mr Sharma's office said the minister was demanding an independent federal investigation into Mr Akhlaq's murder. Calls on Sunday to three officials in Mr Modi's office went unanswered.

At least 16 men from Bisara joined a new militant Hindu outfit called the Samadhan Sena (Solution Army) in August.

The group is not formally tied to the RSS but two members told Reuters they would enforce its agenda in every village.

"Akhlaq should not have butchered a cow," said Mr Ajay Singh, a member of the Samadhan Sena in Bisara. "He should not have forgotten that India belongs to Hindus first."