A group of men attacked Junaid Khan and his three brothers last week in an apparent row over seats as they travelled home by train from New Delhi, killing him and injuring one of his brothers.
Indian police have arrested four men on Thursday, over the murder of a 15-year-old boy on a train, the latest in a slew of hate crimes against Muslims in the largely Hindu nation.
The group of men allegedly attacked Junaid Khan and his three brothers last week in an apparent row over seats as they travelled home by train from New Delhi, killing him and injuring one of his brothers.
One brother said the attackers accused them of carrying beef, a meat popular among many Indian Muslims but shunned by most of the country's Hindus, who revere cows as sacred.
Deputy Superintendent Mohinder Singh said police had arrested four men and have identified the chief suspect in the killing, who is yet to be arrested.
Media reports said two of the men arrested were local government employees.
"We have also taken many eye-witness accounts from the daily travellers on this route and are focusing on arresting the knife attacker," said Singh by telephone from Faridabad in northern Haryana state, where the killing took place.
Indian Prime Minister Narendra Modi has condemned this incident.
Killing people in the name of Gau Bhakti is not acceptable. This is not something Mahatma Gandhi would approve: PM @narendramodi— PMO India (@PMOIndia) June 29, 2017
"Four people arrested and the prime minister of the country speaks out against lynching. This is a very good beginning for a country which has seen the worst kind of savagery. I would like to believe that the citizens of the country standing united have yielded a positive result. More power to the conscience of our society," Rana Ayyub, journalist and writer, told TRT World.
"Not in my name" campaign
The news came a day after protests were held in several Indian cities over the recent killings under the slogan "not in my name."
Rights groups have also warned of a culture of impunity for crimes committed against Muslims, often on the pretext of protecting cows and urged the country's Hindu nationalist government to act.
"The pattern of hate crimes committed against Muslims with seeming impunity is deeply worrying," said Aakar Patel, executive director of Amnesty International India, in a statement this week.
The rights group said at least 10 Muslim men had been lynched or killed in public since April in suspected hate crimes.
Last year Modi criticised the vigilantes and urged a crackdown against groups using religion as a cover for committing crimes.
Critics say vigilantes have been emboldened by the election in 2014 of his right-wing Bharatiya Janata Party.
The slaughter of cows and the possession or consumption of beef is banned in most Indian states, with some imposing life sentences for breaking the law.