15 August 2021, Volume 46 Issue 4
    

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    Research Articles
  • LIANG Weiwei, LIN Xianwen, TIAN Yuanyuan, ZHU Huanhui, SUN Limin, WANG Songcai
    Forensic Science And Technology. 2021, 46(4): 331-336. https://doi.org/10.16467/j.1008-3650.2021.0091
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    Objective To confirm with nuclear magnetic resonance (NMR) about the molecular structure of α-acetyl-methyl phenylacetate (a new precursor chemical for designer drug) that was found from a case, and to establish its identification through GC-MS detection plus an attenuated total reflection infrared spectrometer (FTIR ATR) approach for its qualitative analysis. Methods The white powder sample, seized from a case, was dissolved with deuterium chloroform, having its harboring chemical’s structure confirmed with the engendered 1H-NMR and 13C-NMR spectra. The sample was also dissolved into ethyl acetate to subject to GC-MS detection. Besides, FTIR ATR was adopted to have the sample tested. Furthermore, the sample was hydrolyzed under both alkali and acid environment, having the reaction products detected into GC/MS analysis. Results The structure of the chemical substance seized from the involving case was confirmed through NMR, showing its molecular formula: C11H12O3 and systematic name: α-acetyl-methyl phenylacetate. With GC-MS detection, the α-acetyl-methyl phenylacetate was shown of its retention time 12.57 min, leaving the main characteristic fragment ions at m/z 43, 90, 118, 150, and 192. For FTIR ATR test, the α-acetyl-methyl phenylacetate revealed its main characteristic peaks at 3068, 3013, 2960, 2943, 1738 and 1711. Regrading to hydrolysis experiment, the α-acetyl-methyl phenylacetate can be 100% and 95% converted to P2P (1-Phenyl-2-Propanone) in alkaline and acidic environment, respectively. Conclusions The identification of α-acetyl-methyl phenylacetate (one new precursor chemical for designer drug) has been established here, having resulted in the first-time successful verification about hydrolysis of α-acetyl-methyl phenylacetate to P2P. The α-acetyl-methyl phenylacetate, presently an unregulated precursor for drug production, can therefore provide a reliable reference for its controlling and qualitative analysis with the discoveries here.
  • QIU Lirong, ZHANG Cuiping, DENG Zhenhua
    Forensic Science And Technology. 2021, 46(4): 337-341. https://doi.org/10.16467/j.1008-3650.2021.0030
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    Objective To explore the diagnostic value of three-access MSCT (multislice spiral computed tomography) imaging for rib fracture so as to evaluate the appropriate examination time and methodical choice. Methods The MSCT-imaging materials were collected with 138 cases of thoracic trauma plus rib fracture photographed between November 2014 and October 2018. The collected imaging materials were the ones from MSCT examinations performed within 1 week after injury and those of post-injury 2, 4 and 8 weeks. The amounts of rib fracture were individually noted out from the detection through three-access MSCT imaging choices at different time after injury. Results A total of 542 rib fractures were detected in the 138 samples, with ones from CT axial position, MPR (multi-planner reformatting) and 3DVR (three-dimensional volume rendering) respectively indicating 500, 512 and 457 counts within 1 week after injury. Further, the above three-access MSCT imaging choices showed 538, 541 and 527 fractures that were examined for post-injury 2 weeks, consecutively having for post-injury 4 weeks brought out 541, 542 and 541 fractures and for post-injury 8 weeks all demonstrated 542 fractures. Conclusions The three-access MSCT imaging choices are not completely accurate in diagnosing the amount of rib fractures within 1 week after injury. The MPR is of highest detection rate. There is no significant difference among the three-access MSCT imaging choices during 4 to 8 weeks after injury, with the 100% detection rate being basically reached.
  • LI Heyao, GAO Chang, CAI Nengbin, BAO Qing
    Forensic Science And Technology. 2021, 46(4): 342-348. https://doi.org/10.16467/j.1008-3650.2021.0089
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    Objective A Python-based self-adaptive correction was to propose for fingerprints that had been extracted from the surfaces of gradual curvature so that the difficult problem could be solved about identifying the deformed fingerprints after optical development and visualization on curving objects. Methods A calibration-engraved scaling ruler was used to measure the curvature surface where fingerprint was deposited. Based on the measurement and calculation of the deformation from the ruler’s calibration, a correction approach was set up through Python3.4 programming plus devisal so that both the optimal matching surface and magnification rate were to figure out adaptively, making the distortion eliminated with reverse transformation. Therefore, a revision can be carried out into bringing the fingerprint to proximity to its original pattern. Results The fingerprints on simple curving radius-fixed surfaces have been able to correct with obvious effect under the average error of 5.3%, contrasting to the 7% from HGXJ-360, the Curvature-surface Physical Evidence Image Flattening System developed by Evidential Materials Authentication Center of Shanghai Public Security Bureau. For the fingerprints on complex surfaces of changing curvature radii, significant correction effects have even been attained furthermore. Conclusion The correction approach established here can automatically revise the fingerprints on various curved surfaces towards proximity to their original patterns, demonstrating effective for fingerprints on both the simple radius-fixed curvature surfaces and complex radius-changing ones, therefore capable of providing strong supports with nondestructive extraction of fingerprints on various surfaces in crime scene investigation.
  • DAI Fen, LIU Hongwei, FAN Jie, LI Lu
    Forensic Science And Technology. 2021, 46(4): 349-353. https://doi.org/10.16467/j.1008-3650.2021.0090
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    Presently, illicit and maleficent cases are gradually increasing among the new telecom fraud crimes by way of mobile phone-implanted malicious programs to defraud and/or gamble online. Android application package (APK) was here parsed into electronic forensics so as to provide reference and impartation for investigation of relevant network fraud cases. The mobile phone-operated APK was therewith dissected into its structure, extraction method, reverse-analysis tool and access authorization. Through one actual case, the electronic forensics were probed into the mobile phone-running APK from both static and dynamic analysis. Static analysis was used to fix such the evidence that reverse-analysis tools can be deployed to decompile the APK file, analyze the source function plus its effect, and find the returned mailbox. The dynamic analysis was adopted to simulate the mobile phone-operated APK through an Android simulator, test the packet capture with Fiddler, unveil the network behavior of APK, and eventually fix the case-involved contents as evidence.
  • DENG Hongming, REN Lu, YAO Li, YANG Wenbo
    Forensic Science And Technology. 2021, 46(4): 354-359. https://doi.org/10.16467/j.1008-3650.2021.0092
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    Objective To measure the motion and stability of knee joint in three-dimensional space with Euler angles so as to provide a theoretical basis for gait classification and recognition with new-discovered gait features. Methods The Codamotion three-dimensional motion capture system was used to record the movement and activity confine around the marked legs’ sites of the subject who made 20 rounds of natural walking course, thereby having calculated the Euler angles (X: of adduction and abduction, Y: of internal and external rotation, Z: of flexion and extension) of left and right knee joints. The knee joints were therewith explored of their sports situation. Results Through Spearman analysis being conducted into the calculated Euler angles of knee joints from same person who made multiple rounds of walking course, the coefficient r was received with its 88.60% falling into high correlativity scope and the remaining 11.40% leaving among the significant correlation degree. During the period of single-foot/bipedal support, the swinging/rear-supporting leg led out more stable Euler angles X and Z of knee joint than the supportive/front-supporting leg whose Euler angle Y was yet more steady. Conclusion Same person, when naturally walking into rounds of course, is able to maintain his/her knee joint movement within a certain degree of stability.
  • ZHAO Jingyou, LIU Chao, ZHAO Jiaxiang, GONG Dan, YANG Ya
    Forensic Science And Technology. 2021, 46(4): 360-364. https://doi.org/10.16467/j.1008-3650.2021.0093
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    Objective To develop a method for identifying 5F-AB-PINACA, 5F-AMB, AB-FUBINACA and AMB-FUBINACA of novel synthetic cannabinoids (SCs) through approaches of GC-MS, LC-MS/MS, FTIR (Fourier transform infrared spectroscopy) and RS (Raman spectroscopy). Methods GC-MS was adopted to analyze the methanol-dissolved reference substance (enclosing 5F-AB-PINACA, 5F-AMB, AB-FUBINACA and AMB-FUBINACA) that was further diluted with ultra-pure water for LC-MS/MS analysis. For FTIR and RS analysis, a small quantity of reference substance was directly placed onto ATR affix or glass slide to undergo consecutive detection. Results For either 5F-AB-PINACA against 5F-AMB or AB-FUBINACA against AMB-FUBINACA, their respective characteristic fragment ions are very similar under both GC-MS and LC-MS/MS, with the relevant fragmentation mechanisms being briefly described. Through FTIR and RS, the infrared absorption peaks and Raman displacement peaks of the two substances from each compared pair are of single-one-cannabinoid-based high specificity and selectivity with their individual various modified functional groups. Conclusion Simultaneous application of chromatography-mass spectrometry and spectroscopy into identification of novel synthetic cannabinoids is eligible for providing data able to confirm with mutual reference.
  • XU Chen, LI Xiaofei, ZHANG Yunfeng, YING Jianbo
    Forensic Science And Technology. 2021, 46(4): 365-369. https://doi.org/10.16467/j.1008-3650.2021.0094
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    Objective To develop an analytical method for simultaneous determination of seven rodenticides (TETS, fluoroacetic acid, bromadiolone, brodifacoum, warfarin, coumatetralyl and flocoumafen) (categorized into 4 major kinds) in whole blood through ultra-high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). Methods The samples were treated with acetonitrile to precipitate protein, successively extracted through purification of PLD+ polymer column or organic microporous filter membrane. Luna Omega PS C18 chromatographic column (2.1mm×100mm, 3µm) was adopted for chromatographic separation with gradient elution. The analytes were detected under the mode of negative-ion ESI in full MS/ddMS2. Results Detection limits (LODs) of the seven rodenticides varied among 10~50 ng/mL. The recoveries ranged from 85.3%~94.7% at three spiked levels in whole blood. The intra-day relative standard deviation (RSD) was 3.4%~11% (n=6), with the inter-day’s being 5.6%~13% (n=6). Conclusion This method is both qualitative and quantitative, capable of simultaneous and accurate screening of seven rodenticides in whole blood.
  • JIA Changming
    Forensic Science And Technology. 2021, 46(4): 370-373. https://doi.org/10.16467/j.1008-3650.2021.0095
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    Objective To probe into the applicability of telecentric lens in photographing evidential traces by way of comparative experiments. Methods Under the identical light circumstance, the same surface was respectively photographed with a conventional magnification-constant camera equipped of lens of either macro or telecentric. The comparison was made into the items of field depth, definition, deformation, and edge fidelity of the shot images. Results The conventional macro lens rendered poor field depth when the large aperture as the choice, in contrast to utilization of small aperture (F/16) having achieved the improved field depth yet occurrence of deformation, the decreased clarity and nonuniform brightness. The telecentric lens delivered the shot image of better balancing in both the field depth and deformation together with the even brightness and high sharpness. Conclusion The telecentric lens is of certain applicability in photographing evidential traces.
  • CAI Yugang, WU Yongfu, ZOU Bo, WANG Wen, ZHANG Lian, CHANG Jing
    Forensic Science And Technology. 2021, 46(4): 374-377. https://doi.org/10.16467/j.1008-3650.2021.0096
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    Objective To establish an LC-MS/MS method for determination of flualprazolam in blood. Methods Automatic rapid solvent extraction (ASE) was adopted to extract flualprazolam in blood. The extracted chemical was subjected to analysis of LC-MS/MS. Results Good linear relationship was present with peak area among 0.1~100ng/mL of flualprazolam in blood, with the involving limit of detection (LOD) being 0.05ng/mL, limit of quantification as 0.1ng/mL, and recoveries within the range of 75.4%~95.3%. Conclusion This method is of fast extraction speed, simple operation, low detection limit, high recovery rate and good reproducibility, therefore suitable for determination of flualprazolam in blood.
  • QIAO Jing, ZHANG Wenfang, ZHANG Ying, YANG Shiyun, LIU Yongtao
    Forensic Science And Technology. 2021, 46(4): 378-382. https://doi.org/10.16467/j.1008-3650.2021.0097
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    Objective To establish a method for detecting blood-harbored glufosinate ammonium through derivatization to undergo into GC/MS analysis. Methods Glufosinate ammonium was extracted from whole blood with methyl alcohol/acetonitrile (2/8, V/V), successively subjected to evaporation at water bath of 80°C, consecutively having its residues resolved into methyl alcohol with which the same amount of acetic anhydride was followed to add for derivatization to perform under the time and temperature respective of 1h and 80°C. Finally, the derivatized product was dried and then resolved with acetonitrile (0.2mL) for detection of GC/MS along with external standard. Results With derivatization of acetic anhydride, the tested glufosinate ammonium got its correlation coefficient about 0.993 from the linear curve within concentrations ranging among 0.5~10µg/mL, having the relative standard deviation of 3.2% (n=3) and limit of qualification of 0.2µg/mL (S/N = 45/1). Conclusion The method is simple and reliable for qualitative and quantitative analysis of glufosinate ammonium in whole blood.
  • Reviews
  • WANG Guoli, JI Anquan, LI Yang, ZHANG Wei, SUN Qifan
    Forensic Science And Technology. 2021, 46(4): 383-388. https://doi.org/10.16467/j.1008-3650.2021.0025
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    Strong evidence can be provided for case investigation through accurate identification of body fluid stains at crime scene so that an importance will have been being attached to the relevant studies. miRNA has recently been becoming a research hotspot for body fluid identification with its merits of stability, specificity and rapidity of detection. qPCR (quantitative PCR) is the so-called gold standard for miRNA detection thanks to its high sensitivity and excellent specificity from the involving fluorescence-based quantitative real-time PCR. However, selection of appropriate reference genes is the prerequisite to obtain accurate and reliable results when relative quantification is the purpose. Accordingly, this article tries to make an overview about the selection of reference genes adopted for body fluids identification using miRNA detection, with the emphasis being put on the concerned research progress, selection methods and application challenges.
  • SHU Cuixia, HUA Weijie, DONG Ying, ZHAO Jingyou, GONG Dan, ZHAO Jiaxiang
    Forensic Science And Technology. 2021, 46(4): 389-393. https://doi.org/10.16467/j.1008-3650.2021.0098
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    At times, cases are suspicious of relating to death from poisoning, yet the traditional toxicological testing is difficult to carry out due to the corpses having decayed into skeletonized remains, fragmented and/or decomposed thoroughly, resulting in unavailability to extract the poisoning chemicals. Accordingly, skeletal tissue is then the only left material for the poisoning substances to extract with such cases although it is not a current welcome sample about doing so. However, skeletal tissue is advantageous in preventing against contamination and decomposition, leaving the potential for toxicological analysis to have the depositing-into-bone toxicants refined with novel and ingenious innovations so that the cold and difficult-to-solve cases could be settled someday. Definitely, the recent publications truly present such endeavors about making the road put through. This paper reviews the comprehensive actuality about toxicological analysis into skeletal tissue. Firstly, the suitable skeletal tissues were commented from the relevant publications, together with their applicable methods including the pretreatment (e.g., cleaning, drying, crushing and extraction) and instrumental utilization. Secondly, the animal experiments were summarized about the drug distribution and metabolic changes in skeletal tissue under different environmental conditions. Thirdly, targeting to the discrepant drug concentrations between marrow and mineralized bone, the adequate treatments were discussed for separating marrow from mineralized bone so as to independently assess the value of a particular skeletal tissue type in detection of a given drug. Finally, suggestions and prospect were put forward about both the problems waiting for solution and progressive trend, having emphasized the mechanism of drug incorporation into skeletal tissue, which drugs can be detected in skeletal tissue, which type of or certain bone is suitable for toxicological analysis, and the others related.
  • LI Guangyao, SUN Zhenwen, WANG Ping, HU Can, ZHOU Zheng, ZHENG Jili, ZHU Jun
    Forensic Science And Technology. 2021, 46(4): 394-400. https://doi.org/10.16467/j.1008-3650.2021.0099
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    Hazardous chemical accidents often cause heavy casualties, great economic losses and serious environmental imperilment due to the chemicals possessing flammability, explosiveness, high toxicity and corrosiveness, therefore likely having brought forth serious endangerment to public safety. From the existing statistical analysis of relevant events, explosion fire is found of the main type of accidents caused with the hazardous chemicals. Presumably, such the accidents primarily link with the involving chemicals into their course of production, transportation, storage and use, among which the most serious casualties are related to the production process. Yet, the accident cause is somehow paid attentions more on non-material sector, e.g., violation against rules and regulations, than on specific materials and related information mining. From the perspective of evidential material investigation, the most important thing should be to collect evidence and test the specific materials. Here, a framework is introduced about building up a database of hazardous chemical accidents based on the information of relating materials, with the applicability of the database being prospected from the information mining into those highly-liable hazardous chemicals and material flow in the production process of such chemicals. Thus, the assortative combination is purposed to realize at “hazardous chemical accidents - material information mining (dangerous substances, material flow status) - evidential material identification”, and provide information inquiry plus judgment reference for the evidential investigation of relevant hazardous chemical accidents.
  • Research and Discussion
  • WANG Jingqun, DING Guangshu, ZHANG Yiwen, QI Ji, MO Xiaoting, LI Wanshui, ZHAO Xingchun, YE Jian, ZHANG Jian
    Forensic Science And Technology. 2021, 46(4): 401-407. https://doi.org/10.16467/j.1008-3650.2021.0100
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    Objective To probe into the genetic diversity of 29 Y-STR loci of Korean-ethnic population in Tonghua area (of China’s Jilin province) and the genetic relationship with other ethnic groups in China. Methods Fluorescent DNATyperTMY29 direct amplification kit was adopted to detect 539 Korean-ethnic unrelated individuals in Tonghua area, having the 29 Y-STR loci genotypes obtained so that the genetic data, e.g., gene frequency, were calculated and the genetic distance was comparatively measured against China’s other 13 ethnic groups. Results There were 219 genes and 531 haplotypes being observed from the tested 539 Korean-ethnic individuals. The haplotype diversity (HD) value was 0.999940. The gene diversity (GD) ranged from 0.9656 (DYS385ab) to 0.3138 (DYS391), with the matching probability (MP) being 0.001917 and the discrimination capacity (DC) 0.985158. The closest genetic relationship showed present between the Tonghua Korean-ethnic population and the same people in Korea’s Soul, with the farthest one occurring to Jilin’s Manchu population. Conclusions The here-tested 29 Y-STR loci revealed a high polymorphic distribution among the Korean-ethnic population in Tonghua area. Both the gene frequencies and polymorphism statistics obtained with this survey can provide basic data for population genetics and/or forensic research and application in that region.
  • YE Fangjian, LU Xilong, LONG Yuan, LIU Guanhua, LIN Min, JIANG Xuemei, DOU Xiuchao, PAN Jiecai, LAN Xinkang
    Forensic Science And Technology. 2021, 46(4): 408-413. https://doi.org/10.16467/j.1008-3650.2021.0101
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    Objective To scrutinize the electronic data changing with its related smart lock which to unlock through Tesla coil so that the key points of crime scene investigation and suggestions are thereby to put forward. Methods A smart lock was disassembled to explore its both fingerprint/password storage chip (MCU: micro control unit or EEPROM: electrically-erasable programmable read-only memory) and mode, consequently having undergone repeatedly to unlock with a Tesla coil such that the data in the lock’s chip were recorded for comparison before and after the unlocking. The hardware-circuit communication of the lock was examined to ascertain which communication mode had been interfered with the Tesla coil. An arbitrary waveform generator was adopted to simulate the interfered communication mode from which the resulting changes were recorded and compared against those caused through Tesla coil disturbing. Consequently, the reason why Tesla coil can unlock the smart lock was to discover. Results The fingerprint and password are found of being stored in EEPROM of the selected smart lock, with the password being kept in the storage mode of plaintext. There are three communication modes of IRQ (interrupt request line), SCL (system clock line) and SDA (static data authentication) between the smart lock’s panel board and MCU. When a Tesla coil opens the smart lock, the communication signal has changed, causing the IRQ program unable to get through and/or being disordered so that all the stored data of password and fingerprint have been completely erased from EEPROM, leaving the door open. Conclusions Tesla coil can interfere the communication signals of smart lock, resulting in the lock’s stored data of password and fingerprint being completely erased from EEPROM and the lock being opened automatically. For crime scene investigation, whether a smart lock has been opened with Tesla coil can be inferred through checking if there is occurrence to changing with the data stored in EEPROM of the lock.
  • YANG Qinyu, CHEN Manchun, LAI Xiaoping, SHAO Wanjun, NING Hanhui, CHEN Rui, ZHAO Wenyong, QIU Shengyuan
    Forensic Science And Technology. 2021, 46(4): 414-417. https://doi.org/10.16467/j.1008-3650.2021.0102
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    Objective To explore with retrospective statistical analysis into the problems that should be paid of attention in diatom detection through digesting organic matter with nitric acid. Methods Evidential materials of 484 cases for diatom test received from 2015 to 2020 were collected, with their harboring diatom in lung, liver, kidney, bone marrow and the controlling water samples being examined by nitric acid method (GA/T-813-2008). The resultant data were statistically analyzed. Results There were respectively 99.16%, 75.52%, 73.96% and 50% detection rates of diatoms in lung, liver, kidney and bone marrow. The aggregate positive rate of diatoms in liver and/or kidney accounted for 89.08%. The majority of diatom observed under microscope from the slide of smearing extra-pulmonary tissue fell among 1~10plus, with about 62.13% hepatic or 62.71% renal tissues being detected of 1~5 diatoms/20g. Conclusion The number of diatoms detected from the extra-pulmonary tissue is generally less than expectation when GA/T-813-2008 method is the adoption. Positive should be admitted if several diatoms are detected without possibility of pollution, requesting that at least two extra-pulmonary tissues should be extracted for the diatom test to improve its detecting rate and that the double check verification had better be strictly implemented to avoid false negative.
  • CAO Zhe, YANG Yu, YANG Chaopeng
    Forensic Science And Technology. 2021, 46(4): 418-421. https://doi.org/10.16467/j.1008-3650.2021.0103
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    Sexual asphyxia is a special mechanical suffocation. The doer of such a behavior generally has unusual or abnormal psychology, eager to pursue special sexual experience/sensation with personal steering of certain devices, means or substantive objects to strengthen sexual stimulation and pleasure. Deaths were therewith likely caused from excessive or wrong controlling during these ill acts. Sexual asphyxia performers mostly adopt the way of hanging although there are other peculiar manners. Adult males are mainly the doers of the ill performance, often naked or wearing female clothes. There are pornographic letters, pictures, images, decorations and appliances frequently found of being left on the scene. The nature of death is primarily by accident and sudden death. Occasionally, murder occurred into sexual suffocation. With the collected 73 cases of death from sexual asphyxia, an analysis was here retrospectively carried out to summarize the main points of forensic identification about such cases, purposing to provide references for forensic examiners to deal with those abnormal deaths.
  • Technical Notes
  • QI Fengliang, GUANG Xiaoli, ZOU Jixin, LIN Leixiang, TONG Changyi
    Forensic Science And Technology. 2021, 46(4): 422-427. https://doi.org/10.16467/j.1008-3650.2021.0104
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    e-Commerce has rapidly spawned with the integration of internet technology, logistics and other related industries. Yet, various crimes are also mingled among the involving activities, e.g., selling counterfeit products. Driven by high profits, offenders often manufacture and sell fake high-end liquors like Moutai through the internet. Different from selling counterfeits offline, manufacturing and selling counterfeit liquors online is virtual and concealed, frequently having brought difficulties for public security organs to investigate. Ordinarily, counterfeit high-end liquors are furtively sold through e-commerce and social network’s micro-business proprietors, indefinitely coalescing into their ever-improvised covert sales purposed for avoidance of detection and exposure. Recently, a new mode has emerged of using internet advertising to seduce customers to purchase counterfeits. Based on a case cracked down by Zunyi municipal public security authorities, this paper analyzed the artifice and peculiarity of manufacturing and selling counterfeit Chinese liquors on the internet. Accordingly, a model was therewith established on monitoring online-selling counterfeit liquors, constructing its principle designed on the appropriate keywords setup and snatching into recognizing the internet-spreading advertisements suspicious of selling counterfeit liquors. With such an approach-collected information and integration into offline pertinent investigation, valuable clues would be provided about the relevant cases and people. Such a model and operation would better protect intellectual property of Chinese liquor industry.
  • LIU Jinkun, LI Chunyu, ZHANG Zhiyong, ZHANG Shuai, LUO Jianxin
    Forensic Science And Technology. 2021, 46(4): 428-432. https://doi.org/10.16467/j.1008-3650.2021.0082
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    Iris recognition, a new generation of biometric identification technology, is of great significance for public security organizations to confirm individual identity and/or crack down on crime. This paper summarizes the iris recognition technology about its concept, applications and key technologies. Exampled with the Iris Identity Verification System of Zhengzhou Public Security Bureau, such an iris operation system was expounded of its architecture and module functions from four aspects of iris collection and verification, data query, statistical analysis and basic information management. Combined with the actual situation of public security, the Iris Identity Verification System was introduced to its practical application scenarios in identity information registration and verification, security maintenance for large-scale activities, handling prolonged and/or long-pending cases, concatenating cases and determining source/origin of unknown corpse. Moreover, prospect was also discussed for iris recognition to play its important role in maintaining social security in future.
  • Exchangeable Experience
  • ZHANG Qing
    Forensic Science And Technology. 2021, 46(4): 433-436. https://doi.org/10.16467/j.1008-3650.2021.0105
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    At times, document examination requires identification about intentional falsification into a document that was formed with inkjet printer to print its original version previously yet conduct added printing to engender the modified one afterwards. Such an identification involves with the techniques about how to authenticate both the printed document and the time to have the document formed. Rationally, it is necessary to analyze the document with its relatively stable and abnormal features so that the discrimination can be carried out between them, leading to a reliable identification. This paper dealt with an actual case of this kind. Through thorough analysis of the periodic occurrence of ink dot in the printed graphics and text, three abnormal features were found in the document, having resulted in a conclusion for their forming reasons based on the mechanism of inkjet printing. Therefore, the evidentially supporting proof was provided on whether the document was given birth from only one time or not.
  • WANG Fanghua, WANG Zongbin, ZHANG Chaoyang
    Forensic Science And Technology. 2021, 46(4): 437-440. https://doi.org/10.16467/j.1008-3650.2021.0106
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    Objective To explore an approach for discovering the suspect’s trace left on victim’s skin where to have the related DNA be extracted and tested. Methods Onto the exposed places of case-corpse’s skin was sprayed the biological evidence-targeting reagent. Afterwards, the biological evidence-targeting device was adopted to observe the fluorescence-emitting spots where to wipe with swabs from which DNA was extracted and tested. Results On the forearm and neck of the deceased were developed latent fingerprints from which mixed DNA STR profile was tested with the suspect’s being enclosed. Conclusion Discovery of biological touch trace, e.g., fingerprint, on corpse surface and having the relevant DNA tested can make more information revealed about the involving case, hence helpful to reconstruct the crime scene.