On 13 September 2005, Mao and her husband, Wu Xuewei (吴雪伟), were both reportedly beaten by police when they gathered with over a hundred other petitioners at Putuo District Court in Shanghai. They were supporting Xu Zhengqing, a petitioner who was facing trial in connection with his attempts to attend a memorial service in Beijing in January 2005. Along with dozens of other petitioners, the couple was detained by the police. Mao Hengfeng managed to escape and tried to continue her protest on behalf of Xu Zhengqing. However, she was detained again and sent back to her residential district, where local police and government officials apparently threatened her with imprisonment if she continued her protests and presented her with a formal police summons for investigation on suspicion of 'disturbing the normal lives of others'.