“蛛丝马迹寻证踪,解难析冤见真情,火眼金睛真豪杰,玉芬英名冠京城”。这是公安部一位领导对房山区公安分局痕检工程师李玉芬的赞誉。一次,房山城关一位看菜地的农民被杀,从现场提取的证物只有半筐圆白菜叶子。夜深了,李玉芬在实验室里用镊子夹住一片片菜叶,翻来覆去寻找证据。终于,她在一片叶子上发现了两处指纹,可惜这两处都缺乏主要特征,没有痕检价值。李玉芬左思右想:罪犯用手拿菜叶,就要用力并留下汗液。用力会破坏叶子的细胞组织,汗里的盐分也要和叶子发生反应,用加温法加快破损处的水分蒸发,留 “Clues to find the trace, solution analysis of innocent injustice, gold eye really heroic, Yu Fen Ying crown crown capital.” This is a leader of the Ministry of Public Security Fangshan District Public Security Bureau marks inspection engineer Li Yufen praise. Once, Fangshan Chengguan a vegetable farmer killed, evidence extracted from the scene only half a basket of cabbage leaves. Late at night, Li Yufen in the laboratory with tweezers to clip a piece of leaves, turned over to find evidence. Finally, she found two fingerprints on a leaf, but both of them lacked the main features and did not have the mark-checking value. Li Yufen Zuo Siquan think: criminals use their hands to take leaves, it is necessary to force and leave sweat. Forces will destroy the leaves of the cell tissue, sweat salt and leaves should also react with the warming method to speed up the damage at the water evaporation, leaving