Lagos - Nigeria's anti-corruption agency is reviving a five-year-old scandal involving one of Africa's richest oil blocs, in which a former petroleum minister and his allies allegedly made $1.1bn and the state oil company $210m.The Economic and Financial Crimes Commission filed suit Tuesday in the federal high court charging former petroleum minister Dan Etete, former justice minister Mohammed Bello Adoke and businessman Aliyu Abubakar with fraud and money laundering of hundreds of millions of dollars in the sale of the bloc. The money came from a Nigerian escrow account at the London branch of JPMorgan Chase, according to the court document.The story of the Malabu OPL 245 oil bloc already is being investigated in the United States, Britain, Italy and France. The accusations are typical of the corruption that has impoverished Nigeria, which has the continent's biggest economy and second-largest oil production.Separately, Nigeria's legislature is investigating why the state got so little of the proceeds of a deal brokered by Bello Adoke in 2011 to resolve an ownership dispute involving British-Dutch oil multinational Shell, Italian Eni, Etete's Malabu Oil, Abubakar's Rocky Top Resources and Nigeria's state oil company.Earlier this year, Italian prosecutors raided the headquarters of Shell in The Hague and Eni in Milan. Global Witness, the corruption watchdog that has long pursued the case, said that "Shell and Eni have always denied knowledge of the corruption at the heart of this deal ... exposed their investors to massive risks and have been tainted by this theft from Nigerian citizens."Etete could not be reached for comment Wednesday on the latest court challenge, though he and the others involved have declared their innocence.Malabu Oil paid $20m for OPL 245 in 1998 under a contract awarded by Etete, who was then petroleum minister in the regime of military dictator Sani Abacha. The bloc is said to hold 9 billion barrels of crude and an unquantifiable amount of natural gas.When civilian rule came in 1999, the government of Olusegun Obasanjo seized the bloc and invited multinationals to bid on it.Ten years later, to end a protracted legal battle preventing exploration of Nigeria's most valuable oil bloc, Bello Adoke, then justice minister and attorney general, brokered a deal by which Shell and Eni paid $1.1bn to Malabu and $210m to Nigeria for an exploration license.