South Korean investigators have concluded that an in-flight explosion caused the crash of a Korean Air jetliner that disappeared Nov. 29 near Burma, killing all 115 people aboard. A spokesman for the Transportation Ministry said debris found in the sea off Burma was from the KAL Boeing 707. The debris, including a scorched life raft and other survival items, indicated a strong explosion, he said. Meanwhile, the Korea Broadcasting System reported that an Asian woman suspected of planting a bomb aboard the jet had broken her silence and talked to investigators. It quoted investigators as saying the woman--extradited from Bahrain, where she was arrested along with a male companion who committed suicide--was either Japanese or Chinese.