On 8 December 2006, Ao was arrested based on a case built by the Macau Commission Against Corruption, making him the highest-ranking official arrested in the history of Macau. Ao had allegedly offered preference in government works projects, and had amassed assets totalling 804 million patacas. On 30 January 2008, Ao was found guilty on 40 counts of bribe-taking, amongst others, and was sentenced to 27 years in prison. Ao was aided and abetted by four family members, who were also jailed for between 10 and 18 years for money laundering. On 31 May 2012, Ao was found guilty of taking bribes of more than 31.9 million patacas, and received a sentence of 29 years in prison. Joseph Lau and Steven Lo are both implicated and have been charged with offering tens of millions in bribes to Ao.