Because of insufficient evidence. Yangzhou Huiwen Beauty Salon, three suspects climbed over the wall and sneaked into Huiwen Beauty Salon in Xiaonan Street, Guangling District, Yangzhou City. They killed three waitresses in the shop with daggers, robbed some money and fled the scene. Shimou, a woman who left the scene alive and slept in the hall, used a copper handle steel knife to commit the crime. This case is the biggest vicious robbery and murder case in Yangzhou since the founding of the People's Republic of China, and it has been listed as one of the top ten listed murders by the Jiangsu Provincial Public Security Department. Yangzhou public security organs have invested a lot of police investigations, and so far there has been no substantial progress.