SEATTLE — A misidentified fingerprint cost federal taxpayers $2 million Wednesday and led to an unusual formal apology to Brandon Mayfield, a Muslim lawyer in Oregon whom the FBI says it wrongly named as a suspect in the 2004 Madrid train bombings.
The federal government "regrets that it mistakenly linked Mr. Mayfield to this attack," according to the apology issued by the Justice Department. It added that the FBI had implemented measures to "ensure that what happened to Mr. Mayfield and the Mayfield family does not happen again."
But Mayfield, who under the settlement can still proceed with a legal challenge to the controversial Patriot Act, said the nightmare he endured could happen to someone else.
"I look forward to the day the Patriot Act is declared unconstitutional and all citizens are safe from unwarranted arrest and searches by the federal government," Mayfield said in a statement.
Mayfield was detained in May 2004 after federal officials matched his fingerprint to one found on a bag of detonators in Madrid after the March 11, 2004, commuter train bombings that killed 191 people.
Two weeks later, however, Spanish police said the print belonged to an Algerian man, and the U.S. government said it had made a mistake.
The case highlighted the error potential for fingerprint matching, which some experts say is unacceptably high.
"This is a tip-of-the-iceberg phenomenon," said Simon A. Cole, a professor of criminology, law and society at UC Irvine and author of "Suspect Identities: A History of Fingerprinting and Criminal Identification."
"The argument has always been that no two people have fingerprints exactly alike," Cole said. "But that's not what you need to have an error. What you need is for two people to have very similar fingerprints, and that's what happened here."
Michael Cherry, president of Cherry Biometrics, an identification-technology company, said misidentification problems could grow worse as the U.S. and other governments add more fingerprints to their databases.
"I really believe there are a lot more Mayfields out there," Cherry said. "We just don't know about these cases because the Spanish police don't always get to oversee them. We simply don't have an identification standard that fits with today's times."
In a report on the Mayfield case in January, the Office of the Inspector General, the Justice Department's internal watchdog, said FBI experts had overlooked "important differences" between Mayfield's prints and those of the Algerian man, and had essentially ignored information from Spanish police that pointed to the other suspect.
"We believe that the FBI laboratory's overconfidence in the skill and superiority of its examiners prevented it from taking the [Spanish report] as seriously as it should have," Inspector General Glenn A. Fine said in a summary of that report.
The Justice Department reiterated its contention that mistakes in fingerprint identification were extremely rare.
"The inspector general made suggestions for improving the FBI's fingerprint identification process, and the FBI has adopted many of those suggestions," said Tasia Scolinos, director of public affairs for the Justice Department.
Mayfield, a former Army lieutenant and a convert to Islam, said Wednesday that the government had "targeted me and my family because of our Muslim religion."
But Fine, in his report, concluded that Mayfield's faith was not the reason the FBI came after him, and he said agency officials had not misused the Patriot Act, which Congress passed after the 2001 terrorist attacks.
President Bush and other defenders of the act say it is an important anti-terrorism tool, but critics say it has handed the government too much surveillance and wiretapping power and tramples on civil liberties. Mayfield's challenge contends the act violates the constitutional guarantee against unreasonable government searches.
Times staff writer Lynn Marshall contributed to this report.