Police in the western Brittany region have detained a 13-year-old boy who they believe is responsible for hundreds of bomb threats that have kept France on tenterhooks since the autumn. An investigation was launched on Thursday to determine the teen’s connection to a series of at least 380 hoax bomb threats, according to the public prosecutor’s office in Rennes and the newspaper Le Parisien. The boy is suspected of making bomb threats throughout France, in particular against airports, courthouses and universities, it said. He admitted that he had acted out of “playfulness” and without any poli…