The missile fired at the US Embassy by Revolutionary Struggle last month reached Greece via Kosovo, police sources told Kathimerini yesterday in what authorities believe is a breakthrough in their investigation. Greek and US security agents have discovered that the rocket-propelled grenade was removed from an army warehouse in Albania in 1994 and taken to Kosovo, where it came into the possession of an arms smuggler. Authorities believe that the arms trader held on to the weapon until 2001 and they are investigating his contacts and dealings in the hope they will find out who smuggled the rocket into Greece. A high-ranking police source said that officers had contacted foreign security services to obtain more information and they hope their investigation will develop further this week. No member of Revolutionary Struggle, the leftist group which claimed the embassy attack, has been caught since the organization became active in 2003.