本文所指的重大疑难案件,是指那些危害严重,影响恶劣,民愤极大的案件中案情复杂,牵涉面广,难以收集到确实、充分的证据的案件.在当前严峻的社会治安形势下,公安机关提高攻克这些重大疑难案件的能力,对于深挖犯罪,贯彻“从重从快”的方针,增大对严重危害社会治安的刑事犯罪分子的打击力度,稳定社会治安大局,有着重要的意义. The major difficult cases referred to in this article refer to those cases that have serious merits, bad influence and great indignation, which have complicated cases, extensive coverage and difficult to collect true and sufficient evidences.In the current severe social order situation, The ability of the public security organs to improve their ability to overcome these major and difficult cases is of great significance to deepening crime and implementing the principle of “focusing on speeding ourselves”, increasing efforts to crack down criminals who endanger public security and stabilizing the overall situation of public order.