While viewing footage from a hotel's CCTV cameras, police came across video showing a man crawling along the hotel's corridors and placing his phone close to the doors so that he could hear guests having sex in their rooms.
Police were first alert to the disturbance when one of the hotel guests noticed a shadow moving outside their door in the early hours of the morning, The Metro reported.
The incident occurred in Jiangjin district of Chongqing, southwest China.
Ms Tang and her boyfriend were staying at a hotel in the province when they realised someone was outside their room. They immediately alerted police, according to Chinese website KuaiBao.