His government has also detained an array of public intellectuals who have been critical of its policies, including cyber-dissidents Liu Di and Shi Tao (who was arrested thanks to Yahoo’s collaboration with the police in identifying him) and freelance writers Yu Jie and Liu Xiaobo. Military doctor Jiang Yanyong was detained in 2003 after he publicly rebutted the Party’s assertion that the SARS epidemic had been brought under control.