A n unmanned aerial vehicle that appeared at a weapons exhibition held earlier this year by the rebels ruling much of Yemen bears a striking resemblance to the kamikaze drone believed to have been used later in a deadly attack against an oil tanker off the coast of Oman, experts told Newsweek . The system used in that operation and others like it have been linked by U.S. officials and other analysts to Iran, but experts also noted the near impossibility of drawing a direct link to any single source. Mercer Street , a Liberia-flagged vessel operating on behalf of a company owned by an Israeli businessman, was hit by two back-to-back explosions in July while sailing through the Gulf of Oman. The latter blast killed the ship's captain, a Romanian national, along with its security officer, a citizen of the United Kingdom. The incident sparked international outrage as the United States and Israel attributed the event to one-way drones built by Iran, which denied any involvement in th