A U.S.-Madrid Link?

From Spanish Basques to Moroccan Muslims to an Aloha, Ore., lawyer? The global probe into the March 11 train bombings that killed 191 people in Madrid homed in on suburban Portland last week, when the FBI took former Army officer and Muslim convert Brandon Mayfield, 37, into custody on a material witness warrant. So far, 18 people have been charged in the attacks, which are being blamed on a Morocco-based cell of Muslim extremists. In March, a plastic shopping bag containing detonators like those used in the attacks was discovered inside a stolen white van near a suburban Madrid train station, U.S. and Spanish officials said. When a fingerprint on the bag appeared to match Mayfield's the first U.S. link in the case the FBI began covert surveillance of him, a U.S. official tells TIME.

Though Mayfield was not charged with a crime, the father of three was jailed last week when authorities grew concerned that information was being leaked to the media. It is possible, U.S. officials say, that Mayfield's print ended up on the bag innocently. A lawyer who prays regularly at a Beaverton, Ore., mosque, Mayfield may have used the bag to send something to a contact in the U.S. or abroad. "The case is exceedingly flimsy," says Mayfield's lawyer Tom Nelson, adding that his client hasn't left the U.S. since 1994.

A former client of Mayfield's connects him to a high-profile U.S. terrorism case. In a 2002 child-custody dispute, Mayfield represented Jeffrey Battle, one of the so-called Portland Seven, a suspected terrorist cell. Battle pleaded guilty last year to trying to join the Taliban to fight the U.S. in 2001. Some in the cell attended the same mosque as Mayfield, who converted to Islam in 1989 when he married a Muslim, according to his aunt Beth Vanetta of Halstead, Kans. Vanetta calls Mayfield a "fairly devout Muslim" and "not at all volatile ... the last person in the family I would expect to get into any trouble."