He's been home for more than a week now, back with his wife and kids and grateful to be putting his life back together. But Brandon Mayfield, the Portland, Ore., lawyer who was wrongly jailed for 14 days as a "material witness" in the deadly Madrid bombings, is still mad as hell. Mad at the FBI, for insisting his fingerprint had been found on a plastic bag used by the terrorists--even though Mayfield hadn't traveled abroad in a decade and the Spanish authorities doubted the print match. Madder still at the Justice Department, for using the material-witness law to round him up on flimsy evidence and then bolstering the shaky case against him by painting him as a Muslim extremist. (The affidavit that helped secure his arrest made much of the fact that he had converted to Islam, is married to an Egyptian-born woman and had once briefly represented a member of the "Portland Seven" in a child-custody case.) "Even though I was arrested as a material witness, don't be confused," Mayfield told NEWSWEEK in a phone interview Friday. "They were telling the judge and the world that they've got a fingerprint that's a 100 percent match... What are the implications of that, legally? It's a death sentence."

Mayfield says the Feds left no doubt that they considered him a suspect, not a witness. When he was arrested at his office on May 6, FBI agents cuffed his hands behind his back. He asked them to remove the cuffs, explaining that he wanted to avoid public humiliation in the parking lot. "The agent said, 'Don't worry about it. The media is right behind us'," Mayfield recalls. "I was pretty blown away. Is this the way they do business? They call in the helicopters, SWAT teams, the whole world, the media?"

Spanish authorities put an end to the ordeal when they announced that the fingerprint actually belonged to Ouhnane Daoud, an Algerian living in Spain. Mayfield was released May 20. The FBI, which once said it was absolutely certain the fingerprint was Mayfield's, now says the print is "of no value for identification purposes." One sign of how badly the case was handled: the FBI publicly apologized to Mayfield, something the bureau almost never does. Mayfield appreciates the mea culpa. "I commend them for stepping up to the plate... and admitting they made a mistake," he says. "I'm from the Midwest, and an apology goes a long way."

But it still doesn't settle the most vexing question: how could the Feds have gotten it so wrong? The FBI has blamed the mistake on the poor quality of a digital copy of the print Spain provided, which confused even its best analysts. The bureau points out that an independent fingerprint analyst hired by Mayfield's defense team also agreed that the print was a match to Mayfield (a claim Mayfield's lawyers confirm). The Feds have further claimed that Spain also believed the FBI had a good match. But Spanish authorities insist that they always doubted the Mayfield connection. "At no time did we give our approval," a Spanish police official told NEWSWEEK. "We kept working on the identification... Obviously we wouldn't have kept working on it if we were already 100 percent convinced."

The Mayfield case has, inevitably, led to questions about the reliability of fingerprints as a crimefighting tool, and the FBI will begin a major independent review of its methods. For Mayfield, that may be enough. Or maybe not. He's still mulling over the possibility of suing the government--giving his accusers a chance to be "material witnesses" themselves.