A long time ago, in city S, it has a amazing killing case (杀人案件). It was a quiet night, a man was walking over a pool, he look around of the road, but there was no one there, so he felt safety.
When he is let his guard down(放松警惕), he hear some one is tracking(跟踪) back of him, then he began to run away from the man, at that moment, the man start to spend all the physical strength he had to seize(抓住) the another man. but the man was not want to be catch by the man running back of him, so he start to running faster and faster. Some time later, the man can't catch him, so he got a knife in his pocket. when he already to kill him, the man fall down on the floor quickly, he felt amazing that why did his target fall down before he kill him.
He walk around the man, than he find a small amount of（少量的） blood on the man's clothe, but he can't find what thing kills him, so he had to call the police to answer this question. Then, some minutes pass, he hear the sound of the police car, as soon as he look back, a policeman get down from the police car, he ask the man the process of the case, but the man can't said anything. At last, the policeman only can take the man to the police station.
But this amazing case are not has the best answer until now, the police headquarter（警察总部） had to identified this is a ghost killing event（事件）.