A chance arrest in the city of Rotterdam and tapped telephone conversations were both key factors behind the move to the heightened terrorist alert that has been in place in the Netherlands since 9 July. On Wednesday, the Dutch Public Prosecution Service and Ministry of Internal Affairs announced that a 17-year-old Dutch Muslim youth had been arrested on 30 June on suspicion of involvement in a raid on a supermarket. A subsequent search of his home allegedly led to the discovery of a number of items which, while they had nothing to do with "ordinary" crime, could be connected with...