At least 15 puppies were found dead inside disposable bags at NRS Medical College and Hospital in Kolkata on Sunday. Two other puppies were found alive and taken to hospital, but one of them died soon after, The Times of India reported on Monday.

The incident came to light when the injured dog jumped out of one of the bags, yelling in pain. Residents of the area opened all the bags and found 17 pups. They reportedly did not allow a Kolkata Municipal Corporation van to take the carcasses away and demanded a necropsy on all the bodies first.

The police have filed a first information report against unidentified people based on a complaint by Putul Roy, the daughter of a hospital employee. Roy reportedly first raised the alarm after watching the dog jump out of a bag.

Roy called up Anita Das Basak, a veterinarian, who reached the spot an hour later. “The puppies, it appears, died at least two days ago,” she told The Times of India. “We found some food particles in a packet [nearby]. They could have been poisoned, but the nature of the poison will be known only after forensic tests. The puppies and the dog, who could be their mother, had been severely assaulted. The dog has a heavily injured eye.”

Meanwhile, a video of two women thrashing some puppies with sticks on the campus of the NRS Medical College and Hospital has gone viral on social media. The video appears to have been shot from a few floors above the site of the incident.

Prantik Chatterjee, an animal rights activist who rushed to the spot where the dead puppies were found, told The Times of India that some people claimed that two women who were seen approaching the ladies hostel at the college had dropped the food packets. “There should have been many people there,” he added. But the police are yet to find any evidence of these claims.

“If the involvement of anyone of the hospital is proved, he/she will be given severe punishment,” Daipayan Biswas, deputy superintendent of the hospital, told the Hindustan Times. Kolkata Deputy Mayor Atin Ghosh also promised that the guilty will be punished.