In June, seven of Strasbourg’s young men from the Meinau neighborhood, who had been arrested in 2014, were tried and convicted on terrorism charges in a Paris court.

But this time the terrorism suspects were different.

They were not 20-something young Muslims adrift in marginal jobs or unemployed. They did not turn up in the French government’s notorious “S Files,” where thousands are listed as potential threats, including some who are subsequently arrested.

But it is precisely the inconspicuous profiles of the latest group that have made the men seem all the more menacing. They did not stand out in quiet neighborhoods where the full beards and veils are unusual.

The grocer sold liquor from his store. If officials have correctly identified them as terrorists-in-the-making, these men would perfectly fit the Islamic State’s injunctions of concealment and dissimulation.

People who knew them from the neighborhood said the men used the internet. One neighbor said he thought that a couple of the men may have tried to go to the war zone, and that recruiters had tried to lure him, too.

There were certainly more obvious candidates for jihad. The four arrested gave no outward hint of radicalization. Many were surprised that the men would hatch a plot, if that is what they did.