DSI expert Pol Lt Col Tawan Mangkang, chief investigator in the case, led Bangkok Governor Sukhumbhand Paribatra and nine top officials of the Bangkok Metropolitan Administration (BMA) to the Office of the Attorney-General (OAG) and handed a file case against them to Winai Damrongmongkolkul, director-general of the DSI's Special Litigation Department.
Col Tawan said the DSI resolved to ask the OAG to indict them for unlawfully granting a 30-year contract extension to the Bangkok Transit System Co (BTSC).
They were also accused of conducting infrastructure-related business without being authorised or granted a proper concession by the Interior Minister.
The DSI said the contract was granted unlawfully to the BTSC on two routes -- Saphan Taksin-Wong Wian Yai and Bang Chak-Bearing extensions.
Col Tawan explained that DSI filed charges against 10 suspects but BTSC Chairman Keeree Kanchanapas, BTSC Managing Director Surapong Laoha-anya and the BTSC itself would not be charged as they acted in good faith.
Mr Winai said that the prosecutors would examine the documents and asked the 10 suspects to hear their decision whether to proceed the case or not on June 28.
Meanwhile, Mr Sukhumbhand submitted a petition seeking fairness from the OAG, complaining that the DSI failed to consider all arguments from the BMA.
He asserted that BMA has done nothing wrong and the contract extension is lawful.