On July 20, 2015, Ling was expelled from the Communist Party of China, and was arrested to face criminal proceedings. Ling's case received significant media attention, since he was the most prominent political figure expelled from the party since criminal proceedings were initiated against former Politburo Standing Committee member Zhou Yongkang. In the party's disciplinary dossier against Ling, he was accused of "violating political discipline, violating political rules, violating organizational discipline, and violating confidentiality discipline." He was further accused of taking in large bribes, aiding in the business interests of his wife, sexual misconduct with "numerous women", and illegally obtaining party and state secrets.
Ling was one of the highest-profile targets (next to Zhou Yongkang and Xu Caihou) of the anti-corruption campaign following the 18th Party Congress spearheaded by Party General secretary Xi Jinping and central discipline chief Wang Qishan. He was the second sitting "national leader"-level figure to be investigated by the party's anti-graft agency, after CPPCC Vice-Chairman Su Rong. Chinese-language media have linked Ling to a mysterious political network composed of prominent politicians and businesspeople with origins in Shanxi called the Xishan Society.