Ukraine has said the Sept. 6 blast, which killed at least 16 people, was caused by a Russian missile. "Evidence collected and analyzed by The New York Times, including missile fragments, satellite imagery, witness accounts and social media posts, strongly suggests the catastrophic strike was the result of an errant Ukrainian air defense missile fired by a Buk launch system," the newspaper reported. It quoted air defence experts as saying missiles such as the one that hit Kostiantynivka can go off course for a variety of reasons, including an electronic malfunction or having a guidance fin that is damaged or sheared off during launch.