Neeraj Bhadana, a MBBS first year student hailing from Faridabad in Haryana, was found lying on the floor yesterday.
The girl was admitted to the hospital situated in the college where she died, they said.
The college management had termed it an accidental death, saying that the girl fell from the fifth floor as she was sitting on the railing.
The post-mortem report, however, found that the girl was strangulated to death and there was no fracture on the body, following which a case of murder was lodged against unknown persons, police said.
A senior officer said police are also probing whether the college administration tried to conceal evidence in the case and if found guilty, a case under section 201 of IPC will be initiated against it.