ABUJA, Nigeria — The cash was handed over in large sacks containing $15 million in $100 bills, bags so heavy that the stoop-shouldered civil servant needed help carrying them.

James Ibori, the governor of an oil-rich state in southern Nigeria, was so desperate to escape prosecution on corruption charges that he tried to pay off the civil servant, Nuhu Ribadu, Nigeria’s anticorruption commissioner. Mr. Ribadu accepted the money, but it was all a ruse.

A bespectacled former police officer with the no-nonsense style of a G-man, Mr. Ribadu did not keep the money, a remarkable act in a nation where corruption is endemic. Instead he deposited it in a government bank vault, evidence of Mr. Ibori’s many misdeeds, and in 2007 Mr. Ibori was arrested. Ultimately the charges did not stick — the governor was acquitted by a Nigerian court. He was eventually convicted of money laundering and conspiracy to defraud in Britain, where he had stashed a hefty chunk of the hundreds of millions of dollars of oil money he was believed to have embezzled.

The outcome of the case is in many ways an emblem of Mr. Ribadu’s career as a corruption fighter in Nigeria, a country Colin L. Powell once called a nation of “marvelous scammers”: a string of partial victories against a seemingly unbeatable foe.