Four people, including a policeman, were arrested Thursday in the gang rape and killing of two Dalit teenage girls in northern India.

The girls, cousins ages 14 and 15, disappeared late Tuesday and their bodies were found hanging from a tree in Kata, a village in the Badaun district of Uttar Pradesh state, according to DNA India, a national newspaper. Dalits belong to a caste near the bottom of the Hindu system and have historically faced widespread discrimination in the country.

"We found the dead bodies hanging from a tree. We have arrested a constable along with 3 others," the superintendent of police told the website.

The National Commission of Women condemned the incident, with NCW member Nirmala Samant calling the gang rape and slayings “a horrific crime.”

"Government has promised that they will provide women safety. But it has not fulfilled yet. Till the government [provides] protection for girls from rape, molestation, such kind of incident will go on," DNA India quoted her as saying.

The crimes spurred protests in the area as demonstrators claimed local police were dragging their feet on the case, the Times of India reported.

Three policeman were removed from duty after they failed to immediately register the cases at the time the girls disappeared, the BBC reported. Two more men are being sought in the crimes, senior police official Atul Saxena told the BBC. He added post-mortem examinations were conducted on the girls Wednesday and authorities are awaiting further results.

"We are still investigating how the girls went missing and were allegedly raped and hung from a tree," Saxena said.

Gang rapes in India have drawn worldwide attention since the 2012 gang rape of a 23-year-old woman on a bus in New Delhi. Jyoti Singh died of her injuries nearly two weeks after the December 2012 attack. The gang rape led to protests in India and around the world.