He came to authorities' attention, presumably, because he is a Lebanese who worked at Washington's Dulles International - the same airport where a team of Arab hijackers boarded a Boeing 757 that later crashed into the Pentagon.
He was working for a security company there under a work visa, although it showed him as being employed by a different firm.
That irregularity - and the full court press to round up possible terrorist colleagues in the wake of Sept. 11 - was enough for officials to take him into custody on Sept. 15. With that, the man, who does not want to be named, joined the ranks of 655 people the US government has detained in the course of its post-attack investigation.
Although little is known about the individuals held in detention cells across the country, concern is rising in some quarters - including the Federal Bureau of Investigation (FBI) itself - that the sweep may have been overly broad.
Investigators' willingness to "go out there and take in every single person that may have done something wrong" is troubling, says a former senior FBI official. Civil rights violations are not his only concern: Several FBI agents working on the case have told him in the past week that the investigation may lack focus. "They are saying it is much more of a blanket approach than a laser approach," he says.
The tactics in the United States contrast sharply with those abroad. In Europe, only 23 people have been arrested and charged with crimes ranging from being a member of a terrorist organization to document forgery, and there have been no mass detentions. Here, more than 650 have been detained, but little is known about the number of arrests or the reasons for them.
US authorities are, no doubt, under much higher pressure from the media and the public to apprehend would-be terrorists, says Kai Hirschmann, a terrorism expert at the Federal College for Security Studies in Bonn, Germany. "Probably, the US authorities are grabbing anybody they can and then making sure how far they were involved in the events of Sept. 11," he says. "The approach in Europe has been to observe Islamic communities, but not to arrest people unless it's sure they are involved in terrorist activity."
The Department of Justice, meanwhile, is revealing little about its probe. It has declined to say in which cities it has picked up people, why specifically they were detained, or how many have been released.
"The sheer number of people brought in is unprecedented," says Ronald Kessler, an author who has written on the FBI. He believes the volume of detainments probably indicates the level of caution and concern among law officers. But others worry that the investigation lacks focus. Many of the people detained - some estimates are as high as two-thirds - are simply foreign visitors being held for items such as expired visas and traffic misdemeanors.
In the case of the Lebanese airport worker, authorities took him in Sept. 15 and released him Oct. 2, after they found no reason to continue to hold him. According to US law, visa violators can be denied bond at the discretion of the Immigration and Naturalization Service (INS), and then held until a hearing - which has to be "speedy," but isn't required to meet any codified time period, says Denyse Sabagh, the man's attorney.
For Ms. Sabagh's client, the police work was probably relatively easy. Because he had been here for about four years, authorities had a long trail to follow. Other detainees who have been in the country for only months take longer to clear.
One reason for the extremely broad dragnet, the former FBI official says, is that the Bureau's antiterrorism office has always worked better in "crisis situations," and the relative quiet on the terrorism front before Sept. 11 may have caught them with their guard down. "They are (saying they're) doing things they should have done months ago, like tracking the movements of suspicious people," he says.
But there are signs that the probe is getting more focused and that hyper-vigilance may be yielding some results.
Although the Justice Department is not officially discussing 200 people it is still seeking, details leaking out suggest that many of them are wanted for more than visa violations.
They have been flagged for reasons ranging from being known to have once met Osama bin Laden to being known as close associates of Mr. bin Laden. One report says a computer repair shop in Louisiana found electronic traces in a hard drive of efforts to hack into sensitive federal aviation computer systems and monitor certain airline flights, including those that were hijacked Sept. 11.