The move was based on the testimony of informants as wells as new evidence and documents investigators collected while probing Si’s involvement in a case of funds misappropriation.

Regarding that case, on September 25, 2009, Si was sentenced to three years in jail on charges of “abuse of power” when carrying out the East-West Avenue and HCM City Water Environment Improvement project.

Si, who is also former deputy director of HCM City's Department of Transport, and his deputy, Le Qua, misappropriated funds earned from leasing a State-owned house on Nguyen Thi Dieu Street in District 3 to Japan’s Pacific Consultants International (PCI).

The money received from the contract between August 2001 and November 2002, estimated at around VND1.2 billion (US$66,500), was not submitted to the State budget but disbursed among 87 officials working in the project.

Si took VND52 million and Qua took VND54 million from the contract. The two officials also used VND350 million for “treating guests”.

The case was brought to light following the Japanese Government’s suggestion that Vietnam investigate allegations of PCI officials paying bribes in order to be awarded contracts.

Previously, four ex-employees with Japan’s PCI claimed that they gave Si bribes totalling US$800,000 in exchange for the provision of consultancy services for the East-West Avenue project.

The bribes were given between 2003 and 2006, at a time when the East-West Avenue project in Ho Chi Minh City was underway, the employees said.

On August 25, the four ex-PCI officials were prosecuted on charges of bribery and violations of Japan's anti-competition laws.