The FBI, of course, raided his wife's home in Maryland last August. This was after some intense surveillence of Jefferson's and Abubakar's dealings. On July 18, 2005, an undercover FBI agent drove Jefferson and Mody to Abubakar's house. There, Jefferson and Abubakar met privately for about an hour. Afterward, Jefferson told Mody, who was wearing a wire, about what Abubakar's conditions were for helping the deal through.
The raid occurred about two weeks later, on August 3rd, shortly after Jefferson told Moldy that he'd delivered a $100,000 bribe to Abubakar. The FBI had detected Jefferson's cell phone signal in the area around midnight, July 31st.
As I noted yesterday, Abubakar is making a run for the presidency in Nigeria now - and apparently running on something like an anti-anti-corruption campaign. It's a distinct possibility that the FBI will be reaching the climax of its investigation just as he's rising to power.
According to The New York Times, Bush administration officials "have been reluctant to speculate publicly about the effect of the investigation of Mr. Jefferson on American relations with Nigeria, which is one of largest exporters of oil to the United States."
But at we're getting close to the point when it will be past time to speculate.