Women in India’s northeastern state of Manipur attacked the house of the main suspect in a sexual assault case that has enraged the nation, state police said on Friday.

The person had allegedly dragged two tribal women onto the streets in May and incited a mob to rape and parade them naked, police said on Friday.

The sexual assault took place over two months ago but it captured national attention after a video went viral on social media this week, triggering unrest in Manipur.

The main suspect, a Manipur resident, was arrested on Thursday hours after Prime Minister Narendra Modi condemned the assault as “shameful” and promised tough action.

Three others also were arrested and police are tracing at least 30 others involved in the crime.

“Local women pelted stones and burnt some parts of the house belonging to the prime accused in a village,” said Hemant Pandey, a senior police official in the state capital Imphal.

We request women to protest peacefully as there is intense unease. We understand their rage,” he said.

The police complaint filed in May stated that an armed mob vandalised some houses and burnt them to the ground in a village in Kangpokpi district before attacking members belonging to the Kuki tribe.

The mob, according to the complaint, then sexually assaulted two women aged 21 and 19 who were paraded naked.

The assault was reported by the victims in May when the state witnessed intense ethnic clashes. The fighting was triggered by a court order that the government should consider extending special benefits enjoyed by the tribal Kuki people to the majority Meitei population as well.

At least 125 people have been killed and more than 40,000 have fled their homes since the violence erupted.

Protests were planned in several parts of India by rights groups demanding justice and swift investigations into the latest incident to raise questions about the safety of women in the country.

“We want to know why police failed to take swift action when they knew that women were raped and paraded naked in Manipur,” said Radhika Burman, a student in eastern city of Kolkata who is led a public demonstration on Thursday.

Hundreds of demonstrators in the southern city of Bengaluru marched, with some banners saying; “Women’s body is not a battlefield”. Thay also questioned the failure of authorities to investigate the case registered by two victims belonging to the minority tribal community in May.

“This is gross injustice and neglect,” said H. J. Lakshmi, of Samakaleena Samajik Sanskritik Vedike, a civil society organisation in Bengaluru.

Similar demonstrations were held in eastern city of Bhubaneswar and in some college campuses across the country.

Modi, who had not made any public remarks about the trouble in a state ruled by his Hindu nationalist Bharatiya Janata Party (BJP), spoke a day after the videos showing women being molested went viral.