Nigeria has ceded control of one of the richest oil blocs on the continent – the Oil Prospecting License 245 bloc (OPL 245) and the country is to prosecute oil giants Royal Dutch Shell and Italian Eni in a corruption scandal worth around $1.2b, reported Oil Review Africa.

The West African country’s Economic and Financial Crimes Commission investigates and prosecutes suspects in the so called Malabu Oil scam, according to a statement from the commission, as informed US News. A petition against the fraud has stated that the government is preparing charges of “conspiracy, bribery, official corruption, and money-laundering” against Shell and Eni.

The OPL 245 bloc was estimated to contain 9b barrels of crude, which can cover all Nigeria’s oil needs for 11 years, but since 1998, there have been disputes over its control. In 2011, Shell and Agip – now Eni – bought the bloc for $1.2b, however, investigators have discovered that the payment to former Petroleum Minister, Dan Etete, was potential fraudulent and that the state oil company only received $210m from the deal, wrote All Africa.

The scandal has drawn in investigators from all around the world including the US and a number of European countries, according to the Nigerian Federal High Court document. Meanwhile, the country has already filed criminal charges against the two companies and against several executives in an Italian court in Milan.