Three of the four accused, including a companion of a hostel mess contractor of the university, were later arrested from Haridwar, they said.
In her police complaint, the 19-year-old girl, pursuing BA-LLB course at Bhagat Phool Singh Mahila Vishwavidyalaya in Sonepat, said she was pushed inside a jeep by four youths on Wednesday morning when she had stepped outside the campus to purchase a notebook from a shop. She was then taken to the fields nearby where she was gangraped.
Incidentally, an all-women police station is located near the campus, which also has private security of its own.
"The traumatised victim broke down before other girls of her hostel and the incident was reported to the police on Thursday evening," a senior police official said.
"A case of abduction and rape had been registered against the three accused, arrested yesterday," Rohtak Range IGP Alok Mittal said, adding that search is on for the fourth accused.
Meanwhile, a large number of students blocked Sonepat-Gohana road since Friday, protesting the incident. They also alleged the hostel warden had tried to suppress the matter by dissuading the victim from lodging a police complaint.
The warden, whom the students also accused of not helping the victim or listening to her, has been removed by the university authorities.
Many agitating students told reporters that there was no proper security and eve-teasing was common. However, the university registrar Asha Kadiyan refuted the allegations, saying there was no security lapse.
Main opposition in Indian National Lok Dal condemned the incident, saying it was another example of increasing "lawlessness" in Haryana.