Kolkata: A female nurse was found dead under mysterious circumstances in a washroom at the West Bengal government-run NRS Medical College and Hospital in Kolkata on Wednesday night. Her body was sent for post-mortem, and as requested by her family, it was taken to Calcutta Medical College and Hospital for the same.The nurse, Rupali Burman, who was on duty in a High Dependency Unit at the hospital, had started her night shift. Burman reportedly went to the washroom. When she did not return for some time, her colleagues went to check on her and found the washroom door locked. When hospital staff broke open the door, she was found lying on the floor, police said. Doctors rushed to see if she could be revived, but they were unsuccessful. Subsequently, around 10:30 pm, she was declared dead. "Police has taken all necessary steps. The detective department will take up the case," a senior police official said. Burman's father has demanded a proper investigation into the incident.Health minister Sharadwat Mukherjee visited the hospital on Thursday morning. "We do not know the cause of death. Police will investigate and the post-mortem report will reveal some answers," the minister said.