NEW DELHI: The Enforcement Directorate (ED) has attached assets worth over Rs 9,700 crore in connection with its probe in a PMLA case against Gujarat-based pharmaceutical firm Sterling Biotech. The attached assets included four oil rigs and an oil field, OML143, in Nigeria, four Panama-registered ships, a gulfstream jet registered in the US and held in the name of SAIB LLC and a residential flat in London. TNS