A former executive at oil company BP in Singapore was charged on Thursday with obtaining $3.95 million in bribes in what the city-state’s anti-corruption agency called one of the largest corruption cases in the country. Clarence Chang Peng Hong, a former regional director for marine fuels with BP, was charged with taking bribes from an executive at a petroleum products supplier in order to advance the company’s business interests with BP, according to the charge sheet from Singapore’s Corrupt Practices Investigation Bureau .