Chennai: Police here are on the look out for two medical college students for throwing a dog off the roof of a multi-storied building, said an animal welfare activist here on Tuesday. "We put the video of a person throwing a dog from the roof-top of a building in the Facebook and got several leads and confirmed that the two persons on the video were students of a medical college," activist Shravan Krishnan said. He said the police were also very helpful in identifying the persons who did the cruel act. The video of the incident, uploaded on social media couple of days back, wrung the hearts of even the strongest as it showed a youth on the roof-top of a multi-storied building was holding a dog which he cold-bloodedly threw off. As the cruel act happened sometime back the fate of the dog is not known. Police also reached the college and held discussions with the college authorities. Reportedly, police have urged the parents of the accused to see that their wards surrender at the earliest.