The beating and subsequent death in New Delhi of a university student from northeast India has sparked an outcry against the incident, and the police have been criticised for inaction.
Officials said on Saturday that 20-year-old Nido Tania from Arunachal Pradesh state was on holiday from his studies in Jalandhar, Punjab, when he was beaten by shopkeepers who had ridiculed his appearance.
Police detained the two shopkeepers and launched a murder investigation on Friday night, after being criticised for doing little following Wednesday's attack in the capital's Lajpat Nagar market.
"We are questioning several people in the case," said Delhi police spokesman Rajan Bhagat.
About 2,000 people took to the streets of New Delhi on Saturday to protest against the suspected racist attack.
Several hundred people protested outside a New Delhi police station on Saturday, demanding justice for what they called a hate crime. The Indian capital's newly elected chief minister, Arvind Kejriwal, asked that a magistrate, as well as the police, investigate the incident.
Racism and discrimination
|People from northeast allege they encounter racism in the rest of India [EPA]
Tania died in bed on Thursday morning and an autopsy is being conducted to determine the cause of the death.
Hundreds of students held demonstrations in front of a police station and near the shop where Tania was beaten in the south Delhi neighbourhood of Lajpat Nagar. They carried placards with slogans including "Hang the culprits," and "Why are we treated like outsiders?"
Many indigenous people from India's northeast, some ethnically closer to people in Myanmar and China, often say they encounter racism and discrimination in the rest of India.
"This was a racist hate crime," said Albina Subba, from the northeast Himalayan town of Darjeeling. "Our community is often targeted like this ... we look different, so it's easy for people to see we're not from Delhi."
"We have little faith in the Delhi police, but this time we want them to take action," she said.