In many criminal cases, eyewitnesses provide critical statements to convict the suspects. The most important hypothesis based on this phenomenon is that the statements of a conscientious eyewitness are reliable. However, lots of psychological evidences show the relationship between the memory and the event is not direct. Without any intention of a perceiver, his or her memory structure is vulnerable to change by a bit of related cues. Therefore, in many cases, the memory of an event would be far different from the event itself. In this paper, empirical evidences are presented to show how event memory is distorted by the presuppositional questions and post-event priming cues. The results of this study showed the memory, the perception, and furthermore the judgement of punishment of crime are affected by the presence of post-event distorting information. However, when informing subjects the presence of a potential distracter, the probable retroactive influence on memory cancelled out.