Nigeria's president has authorised a forensic audit of the national energy company, the presidency said on Wednesday, after weeks of public uproar over an alleged $20 billion in missing state revenues, Reuters reported. Central Bank Governor Lamido Sanusi wrote a letter last September to President Goodluck Jonathan saying almost $50 billion in revenues from oil exports from January 2012 to July 2013 had not been remitted to the federation account, in a clear violation of the law. He lowered the estimate to $20 billion in testimony to a Senate committee investigating the case last month, days before he was suspended by Jonathan for what the president said was unrelated "financial recklessness" and "gross misconduct" at the central bank. Government sources and a wide spectrum of the public believe his removal was politically motivated. The Nigeria National Petroleum Corporation (NNPC) has repeatedly denied Sanusi's allegations and the presidency, which says they are unfounded, has not responded until now to calls for an independent audit. Africa's biggest oil producer and the continent's second-largest economy has a reputation for corruption but the scale of the alleged oil graft is unprecedented and Sanusi is the most high-profile figure to raise issues directly to the president. Sanusi was an internationally respected central bank governor and financial markets were rattled by his suspension with the naira currency briefly dropping to a record low. Nigeria's Finance Minister Ngozi Okonjo-Iweala and a Senate committee investigating the graft allegations have both called for a forensic audit of NNPC since Sanusi presented evidence.