The Xinhua News Agency says the policeman, identified only by his surname, Zhong, and a journalist surnamed Liu are under investigation for bribe taking.
It says the ex-wife and a former lover of spiritual master Wang Lin are suspected of colluding with them to leak documents that could help Wang's case.
Wang claims to have supernatural powers as a master of qigong, but was arrested in August and charged with illegal detention in the kidnapping and murder of a former acolyte.