本文基于公安部刑侦局进行的第三次“剖析命案讲教训”活动,通过对全国各级公安机关上报的近几年四十九份诉讼失败命案卷宗的剖析得出几点教训:一是事实不清,证据不足;二是定性不准确;三是犯罪嫌疑人死亡或者有精神障碍;四是犯罪情节显著轻微,目的是切实提高命案侦办质量。 Based on the third “analysis of homicide lesson” conducted by the Criminal Investigation Bureau of the Ministry of Public Security, this article draws a few lessons from the analysis of 49 cases of unsuccessful murder cases filed by the public security organs at all levels in recent years: The facts are not clear, the evidence is insufficient; the second is the qualitative inaccuracy; the third is the death of a criminal suspect or a mental disorder; the fourth is that the crime scene is obviously mild with the purpose of actually improving the quality of murder investigation.