A small group of extremists lie behind a string of minor bomb attacks over the past year that have severely compromised the country’s image as a secure Olympic host, police told Kathimerini. Senior officers, speaking on condition of anonymity, told Kathimerini that detectives are now focusing on locating the group’s arsenal of explosives, timers and detonators, which has probably been used for several years by a number of left-wing extremists. If the arsenal is found, valuable evidence linking specific suspects could emerge. The sources said police suspect three or four veterans of anti-state groups are at the heart of the organization, which is believed to have claimed responsibility for attacks under different names, in order to convey the impression of a large movement. These people are believed to have enrolled a small number of younger extremists who are unknown to police, in order to handle the group’s operational side. The last attack was at the Larissa central courts complex on May 29, and followed two strikes in Athens earlier in the month. All three were bloodless.