Beijing police have launched a criminal investigation over a complaint that a woman was mysteriously stabbed on the overcrowded subway.

The woman, whose surname is Wang, said passengers at the Pingguoyuan subway station pushed her into the carriage during rush hour on Aug 2. She felt a sudden cut near her bottom, but she was unable to turn around at that time, Beijing Times reported. 

She forgot to take care of the injury. When she arrived at her office, she was reminded by her colleagues due to a the blood stain on her dress. She received simple treatment at Peking Union Medical College Hospital.

To her surprise, she later found her former classmate shared the same experience at the Pingguoyuan Subway Station on the same day on a social network site.

Wang then reported the incident to the police who suggested she take a blood test and receive a vaccination against tetanus at the Di'tan Hospital.

Police are still investigating the case.