Last week, the Daily Independent reported that the FBI found a link between al-Qaeda and the New Year’s Eve bombing in Abuja. If true, it changes much.
However, I can find no confirmation from any United States government source. The "America" doing the "disclosing" may have been FBI agents -- possibly explosive experts -- who have concluded that the bomb technology is the same as that used by al-Qaeda. But that does not necessarily establish an al-Qaeda link. "President Barak Obama has approved" may mean that some part of the USG has agreed to send some technical experts to Nigeria --but, again, no sign of any presidential decision about anything. Further, while an FBI team was dispatched to help with the investigation, it is unlikely that it has had enough time to establish a link.
While the potential exists, I still remain skeptical about al-Qaeda involvement in Nigeria.