Abdulmutallab is talking to the FBI.

FBI agents traveled to Nigeria and enlisted the help of his relatives, who "disagreed with his efforts to blow up American targets."

ADDED: Let's not forget all that criticism about telling Abdulmutallab about his Miranda rights:

Why are we reading Umar Farouk Abdulmutallab his Miranda rights instead of taking him somewhere and forcibly finding out where he got the explosive underwear and whatever else he might know about Al Qaeda? Isn’t this, as well as the forthcoming federal court trial of Khalid Shaikh Mohammed, proof that the Obama administration doesn’t really regard the war on terrorism as a war?...

Republican critics like Dick Cheney and Newt Gingrich have raised these questions in the past few days....

There were ways, apparently consistent with American criminal procedural rights, to milk Abdulmutallab for information. If the first-linked story is true, the success of the method used must be acknowledged and taken into account by those who say that terrorist suspects/enemy combatants must be treated differently from those accused of ordinary crimes.