NEW : Men in custody may have been testing security . NEW : The FBI is investigating the incident, but it's unclear if they are looking into whether or not there was a connection between the two incidents. U.S. law enforcement officials told CNN that the checked bags contained knives and box cutters as well . Arrests follow Chicago-to-Amsterdam flight . Dutch investigators keep lid on details .
NEW : Men in custody may have been testing security . NEW : The FBI is investigating the incident, but it's unclear if they are looking into whether or not there was a connection between the two incidents. Arrests follow Chicago-to-Amsterdam flight . Dutch investigators keep lid on details .