A foiled plot to attack New York synagogues offered a distressing reminder to the Jewish community that Osama bin Laden’s death does not mean an end to the threat of terrorism — especially from so-called “lone wolves.” New York police arrested Algerian-born Ahmed Ferhani, 26, and Mohamed Mamdouh, 20, a naturalized American citizen from Morocco, on May 11 in Manhattan. Police made the arrests, the result of a seven-month investigation, after Ferhani purchased guns, an inert hand grenade and ammunition from an undercover detective.