According to the woman's family, she did not inform anyone about the incident for weeks and kept crying.

The police on Friday registered a case against four unidentified persons for allegedly raping a 19-year-old woman on her birthday in Mumbai's Chembur area on Friday.

The police have registered a 'Zero FIR' and transferred it to Chunabhatti police station.

The woman was on her way back from her friend's house on July 7 after her birthday celebrations when she was allegedly raped by four men. According to the woman's family, she did not inform anyone about the incident for weeks and kept crying.

After her condition deteriorated, she was taken to a hospital in Aurangabad, where the doctor revealed that she was raped. The woman then informed the family about the incident.

"We have registered an FIR against four unidentified persons under Section 376 (rape), 376D (gang rape) and 34 (criminal acts by several persons in furtherance of common intention) of Indian Penal Code (IPC)," said police inspector Deepak Vijay Surve.

Investigation in the case is underway.