The Indian police said Thursday that three men have been arrested in Rajasthan state on charges of assault and murder after they attacked a group transporting cows.

A group of 15 Muslims was attacked by a 200-strong mob on a highway in Alwar district on Saturday over suspicions that they were smuggling cows for slaughter.

Five men were seriously injured and one of them, Pehlu Khan, 55, later died in hospital.

The men were dairy farmers who had bought the cows from a market in Rajasthan’s capital, Jaipur, and had all the requisite documents, Indian Express newspaper reported.

Hindus regard the cow as holy.

Cow smuggling is a punishable offence in Rajasthan and its slaughter is banned in most Indian states.

Federal Home Minister Rajnath Singh said: “Whatever the incident, the Rajasthan government has taken action, reports with police have been filed and our government will see that law takes its own course.”

Rajasthan Home Minister Gulab Chand Kataria said police had lodged cases against both sides , of cow smuggling against the men who were attacked and of manhandling and murder against their attackers, and were probing all angles, India Today news channel reported.

Opposition parties attacked the government on the issue in both houses of parliament Thursday.

The Hindu nationalist Bharatiya Janata Party runs the federal government and that in Rajasthan state.

“There was a mob of 200 people and only three arrested … If you let things go on like this peace will be destroyed in this country,” said Mallikarjun Kharge, a lawmaker for the opposition Indian National Congress Party.