On June 4, 2013, state media announced that Ni was being investigated by the
Central Commission for Discipline Inspection of the
Chinese Communist Party for "serious violations of laws and regulations". The party investigation concluded that Ni had abused his power to seek benefit for others, taken "massive amounts" in bribes, and was "morally depraved". On September 30, 2013, he was expelled from the Chinese Communist Party, and sacked from all his government posts. He was formally arrested on October 17. His case was moved to judicial authorities for prosecution. Ni's trial took place at the intermediate court in
Dongying, Shandong province beginning in December 2014. The prosecution alleged that Ni received kickbacks such as luxury trips and renovations to his home in exchange for giving favourable treatment to a local entrepreneur; Ni was also said to be responsible for wasting some 1.9 billion yuan (~$307 million) in government resources. The prosecution referred to a large personal
jade collection as evidence of Ni's corruption. The court found that Ni took bribes – in the form of cash, jade, and calligraphic works – on some 49 different occasions during his tenure as Vice Governor, worth the equivalent of 13.48 million yuan (~$2.15 million). He was also said to have taken bribes in the form of home furnishings, debts forgiven to his relatives, and retail cash cards. Moreover, some 5.8 million yuan ($930,000) of his assets were of unclear origin, which also constituted a criminal offense. The Communist Party-run ''People's Daily'' wrote an editorial that compared Ni's obsession with jade with an ancient ruler from the 660s BC who diverted state treasury to fund his hobby of raising
cranes. Ni also reportedly complained that he would not have committed the most egregious offenses had his superiors and party disciplinary authorities simply warned him about the nature of his conduct, implying essentially that he 'wouldn't have done it if he knew he would be caught.' Along this theme, several Chinese newspapers ran commentaries that rule of law and better enforcement of discipline were the best means to prevent corruption. ==Personal life==