Two students were arrested on Tuesday in connection with the killing of 16 puppies outside Kolkata’s Nil Ratan Sircar Medical College and Hospital. The animals were found dead in a plastic bag outside the hospital on Sunday.

“Both the students were remanded in police custody for further interrogation,” News18 quoted the Kolkata Police as saying. The students, Moutusi Mondal and Soma Burman, had confessed to the crime.

Preliminary reports said that the animals were beaten to death, PTI reported. Police believe that more students might have been involved in the killings.

A video showing Mondal and Burman violently beating up the animals had gone viral. Animals lovers had protested outside a police station in Kolkata, demanding that action be taken after the killings came to light.

An unidentified senior police officer said the two students were arrested with the help of the video and after two security guards identified them, reported The Times of India. The officer said the two students have named others who helped them. Police are questioning them now, the officer said, adding that the club used to beat the puppies have been recovered.

A three-member hospital inquiry committee had questioned around 55 students. The hospital’s Deputy Superintendent Dwaipayan Biswas, who led the inquiry, said the police will take action. “Extremely strict action will be taken against the guilty,” Biswas said.

An unidentified senior hospital official said the students and staff members had planned the murder. “They lured the puppies from different corners of the hostel premises with biscuits and, once they were inside the hostel backyard, all exits were blocked.”