Yes, he was being detained.
Transportation Security Administration officers escorted Mr. Bierfeldt to a nearby interview room, where he was interrogated for more than 20 minutes by screeners and then by the police officers who were soon summoned.
“What do you do for a living?” a T.S.A. officer named Ron Bardmass asked Mr. Bierfeldt.
“Am I legally required to tell you that?” asked Mr. Bierfeldt, who lives in Virginia and was flying home.
And then, according to a transcript of the encounter that was later released as part of a lawsuit, Mr. Bardmass persisted, “You may not be legally required to tell me that, but you will be legally required to tell it to the police officer who comes to talk to you.” He added, “I’m just trying to ask some questions to figure out what this is about so I can get you on your plane.” But, he went on, using an expletive, Mr. Bierfeldt seemed to want to play games “and I’m not going to play.”
Mr. Bardmass later said in court papers that Mr. Bierfeldt’s “evasive behavior” led him to call the airport police to help sort out “possible evidence of criminal activity.”
Unfortunately for the interrogators, Mr. Bierfeldt was carrying an audio recorder. “As I was being led into the room, I thought, ‘This is going to be a bigger deal than I thought,’ so I took out my iPhone in plain sight, played a little with it, pushed record and put it back in my pocket,” Mr. Bierfeldt said.
The transcript of Mr. Bierfeldt’s recording shows that the officers, evidently unaware that Mr. Bierfeldt was recording the session, threatened Mr. Bierfeldt with federal arrest for declining to account for the cash. Mr. Bierfeldt kept asking politely whether he was legally required to answer. This intransigence irritated the officers.
It is not illegal, by the way, to carry a large amount of cash while traveling. (The law does require cash amounts over $10,000 to be declared on international trips.) And as the American Civil Liberties Union argued in a lawsuit filed in June against the T.S.A. in the Bierfeldt case, screeners exceeded their authority in detaining him and demanding explanations once Mr. Bierfeldt had cleared standard checkpoint security inspection.
Last week, the A.C.L.U. said it dropped its suit after the T.S.A. clarified its policies in late September. The agency told screeners that, while they were encouraged to refer any suspected criminal activity or illegal contraband discovered in a checkpoint search to law enforcement officials, their job was to screen for weapons and verify passenger identities. “Traveling with large amounts of currency is not illegal,” the T.S.A. added in an internal directive on Oct. 29.
Mr. Bierfeldt, it turns out, was carrying the money because he was returning home from a regional conference of Campaign for Liberty, a group that supports Ron Paul, the former presidential candidate. Mr. Bierfeldt, the group‘s development director, said he often traveled from political events with donations and money from the sale of T-shirts and bumper stickers.
The T.S.A. said it was “pleased with the outcome of this lawsuit.” In an e-mail message, Sterling Payne, an agency spokeswoman, said that “currency alone is not a threat.” She added that the agency “will continue to work closely” with local, state and federal law enforcement officials to refer “potential evidence of criminal wrongdoing.”
Ben Wizner, an A.C.L.U. lawyer for national security issues, said the organization did not object to aggressive security enforcement by screeners. The crucial issue, he said, is the threat to Fourth Amendment guarantees against unreasonable searches by screeners who overstep their limited authority.
“This is important because the encounter Americans have with T.S.A. screeners is the most common Fourth Amendment event in American life,” he said.