After the bombing, Israel sent investigators to Argentina to search for clues. They learned that the bombers planned the attack in the Tri-Border area, where the borders of Argentina, Paraguay, and Brazil meet and which has a large Muslim population.[6] Messages intercepted by the American National Security Agency revealed Iranian knowledge of the impending attack, as well as the complicity of Hezbollah operative Imad Mughniyah.[6] In fact, Mugniyeh was formally charged by Argentina with participating in the bombings of the Israeli embassy.[7]