Ibori was not only a state governor when he committed the alleged crimes, he was also a powerful member of the ruling People's Democratic Party (PDP) and a financier of the presidential campaign of President Shehu Yar'Adua, now late.

BBC: African viewpoint: Scramble for Nigeria's $15m 'bribe'

When he took the cash to the CBN in 2007, he said that it was a bribe given to him by James Ibori, then governor of the oil-rich Delta state, to stop the investigation of allegations of monumental corruption against him.

BBC: African viewpoint: Scramble for Nigeria's $15m 'bribe'