NEW DELHI (Reuters) - Indian police have arrested two Hindu farmers in connection with the killing of a Muslim man suspected of smuggling cows to a slaughter house, the investigating officer said on Wednesday.

Hardline Hindu groups have gained prominence since Prime Minister Narendra Modi’s nationalist Bharatiya Janata Party came to power in 2014, and the protection of cows, considered holy by many in the Hindu-majority country, is a priority for them.

Police found the body of Ummar Khan, 35 on Friday on railway tracks in Alwar district, in the northwestern state of Rajasthan.

The two suspects were detained on Monday and arrested the next day, said Rahul Prakash, the top police officer in Alwar.

“It is a clear case of murder over the issue of cow protection and we have also found that the victim was running a cow-smuggling racket,” Prakash said.

Khan and two accomplices were using a stolen vehicle to transport five cows when they were attacked by six members of a self-styled cow protection force, he said.

“Both sides were carrying guns and were shooting at each other.”

Khan was shot dead and his body was thrown onto the railway track, Prakash said.

Cow slaughter is illegal in most of India.

“Gau rakshaks”, or cow vigilantes, run a loosely organized movement that they say is meant to prevent cattle smuggling, with tactics that include highway ambushes.

Modi has called for more to be done to prevent such attacks on people accused of eating beef or slaughtering cows.

This year, a Muslim farmer died from injuries sustained during an assault by a mob in Alwar, about 180 km (100 miles) southwest of New Delhi, when he was taking cows to his home.

Khan’s wife, Khurdisan, denied that her husband and been leading any cows to slaughter. She accused members of a right-wing Hindu group affiliated to Modi’s party of the murder.

“He was bringing the cows home for their milk, not for their meat. I want the government to protect me and my children,” she was quoted as saying by Hindi-language Rajasthan Patrika newspaper.