Sansern Pholjiak, NACC’s secretary-general, said the anti-graft body will have to seek approval from its board to expand the investigation to cover the governor’s role in this case as the Office of Auditor-General’s findings show that Sukhumbhand violated the state procurement law.

So far, NACC’s subcommittee chaired by Suwana Suwanjutha has found that Chumphol Sampao-phol, a deputy Bangkok governor, and other officials, could be guilty for favouring a private company to win the contract.

Earlier, the Interior Ministry also ordered the BMA to set up a committee to investigate the case, which could lead to Sukhumbhand’s impeachment if two-thirds of the city’s councillors endorse the proceedings.

Sukhumbhand has threatened to sue the Office for damaging his reputation in relation to this case.