 16 of those on board were killed; three survived.Investigators believed that the explosion had been caused by a time bomb placed aboard the aircraft by a secret agent of the Kuomintang, also known as the Chinese Nationalist Party, who was attempting to assassinate Chinese premier Zhou Enlai, who had been scheduled to board the plane to attend the conference but had changed his travel plans at the last minute.Kao, along with British and Chinese agents, probed the circumstances leading to the crash.