基于数据库数据分析的DNA证据作用评价

A Preliminary Evaluation of DNA Evidence in Criminal Investigations Based on National DNA Database

始建于2003年的全国公安机关DNA数据库10余年来累积了千万级的数据信息，其中除DNA分型等技术数据外，还包括大量的案件、物证、人员的相关信息。本文尝试以DNA数据库的相关数据为基础，选取2011~2014年的部分数据，从时间、物证类型、案件类型、比中率等多个维度进行综合比较，对DNA证据在刑事案件中的价值和应用进行较为系统的分析。结果显示：目前DNA证据在破案和串并案件中的有效利用率接近50%，在刑事案件，特别是强奸、杀人案件中的比中率（MRe）平均高达71.1%和62.1%，具有不可替代的作用；DNA证据在打击职业性犯罪中的作用越来越显著，2011~2014年，盗窃案件中的物证增长了124.0%，比中数量提升了55.3%；非刑事案件对DNA证据的需求显著增长，2011~2014年，毒品类犯罪物证增长了477.3%，比中数量提升了378.6%。通过对常见生物物证的实用价值分析，发现传统的生物物证仍是DNA实验室的主要检测对象，血液（斑）、精斑、唾液斑（包括烟蒂）占到了总量的82.8%，同时检测对象的种类也在不断的拓展之中，2011~2014年，脱落细胞类数量增长了241.7%，比中数量提升了158.5%。最后提出了不同类型案件现场勘查中应关注的典型物证的建议。

For the last decade, China national DNA database has expanded exponentially, and held tens of millions of data, including not only the DNA proifles, but also a large amount of relevant information, related to crime scenes, evidence, individuals, etc. This paper attempts to evaluate the function of DNA evidence and DNA analysis in criminal investigations. Data in the national DNA database uploaded from 2011 to 2014 was selected, and a systematic analysis is carried out on multiple dimensions, such as time, evidence type, crime type, match rate, etc. As expected, DNA analysis has an outstanding performance in criminal investigations either in case solving or crime linking with the effective utilization rate close to 50%. It emerges as a powerful tool in criminal investigations, especially in rape cases with matching rate of evidence （MRe） of 71.1%, and murder case at 62.1% of matching rate. The DNA evidence also plays signiifcant role in ifghting against professional crimes from 2011 to 2014, in which the evidence for theft and drug cases rises to 124%, 477.3%, and the match number up to 55.3%, 378.6%, respectively. By the systematic analysis of the practical value of common biological evidence, it reveals that traditional biological sample, like blood, semen and saliva （including cigarette butt）, covers 82.8% of all the samples detected in DNA laboratories, while new types of samples are becoming more popular. During the same period of time, the number of touch DNA evidence has a growth of 241.7% in total and the match number rises to 158.5%. This paper also proposes that the key evidence should be carefully collected according to the speciifc type of crime scene to make sure that the evidence won’t be compromised in the following investigation and litigation.