Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
In video investigation work, high-quality surveillance video portraits can provide a lot of effective information about criminal suspects, help investigators determine the direction of investigation, narrow the scope of investigation, and lock the criminal suspect. However, it is often encountered that the quality of video face images are too low to be recognized and facial image depth restoration methods such as GFP are only suitable for the restoration of a single facial image. To this end, this paper proposes a video facial image restoration technology based on the GFP, which extends the GFP method to the application of video investigation, facilitates the timely locking of criminal suspects in the video investigation work, and improves the efficiency of solving cases. Firstly, pre-processing operations such as video framing, facial image crop alignment, and oblique perspective correction are performed on the surveillance video. Then the GFP method is used to restore the depth of the pre-processed facial image. Finally, the restored face images through the reverse processing such as facial image registration, image restoration and video synthesis to generate high-quality facial image video. This paper verifies the effectiveness of portrait restoration technology based on GFP through simulation experiment, practical application and comparison experiment. Among them, simulation experiment and practical application were carried out on a large number of pre-processed real degraded face images and simulated degraded face images. The results show that the GFP is superior to other facial image depth restoration methods in terms of subjective visual effects and objective quantitative index such as FID, PSFR, SSIM, and NIQE. And by using YTF facial image video data set for comparison experiment, the experimental results show that the method of adding pre-processing and reverse processing is superior to the traditional GFP method. The video portrait restoration technology based on GFP with pre-processing and inverse processing proposed in this paper has better restoration effect for low-quality video portraits.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
To study the qualitative analysis of unknown quinazolinone in suspected tablets without reference substance, the new compound discovered from a dubious package called “Huyouyou” seized by the police was tested with methaqualone standard materials and etaqualone standard materials by gas chromatography-mass spectrometry (GC-MS). The retention time of unknown compound is closed to methaqualone and etaqualone, and ion fragment m/z 235 existed both in spectrogram of methaqualone and the unknown compound. There were not any satisfying matching search results in NIST20s and new psychoactive substance (NPS) spectral library Cayman Spectral Library, and the unknown compound was suspected to be a new quinazolinone. Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was further used to analyze the structures of methaqualone standard materials, etaqualone standard materials and the suspected new quinazolinone. The first-grade fragment and second-grade fragment information of methaqualone standard materials and etaqualone standard materials were consistent to potentially lytic pathway. Possible molecular formula of the suspected new quinazolinone by software Formula Predictor as C16H14N2O2. According to the second-grade fragment information, the suspected new quinazolinone had a quinazolinone nucleus structure and an attached phenyl ring, but the molecular weight was 2 daltones larger than the etaqualone, suggesting a methyl moiety is replaced by oxygen. Chemical structure of the suspected new quinazolinone was predicted as 2-methyl-3-(2-methoxyphenyl)- 4(3H)-quinazolinone. Nuclear magnetic resonance (NMR) was finally used to estimate the suspected molecular formula 2-methyl-3-(2-methoxyphenyl)-4(3H)-quinazolinone.1H-NMR and 13C-NMR data supported the location of the oxygen, the locations of the carbons and hydrogens were also estimated simultaneously. The chemical structure of the suspected new quinazolinone was finally verified by NMR, and the new quinazolinone was suggested to be named as methoxyqualone.
Abstract (
)
Download PDF (
)
HTML
(
)
Knowledge map
Save
The synthesis of three β-substituted ninhydrin derivatives and their application to the development of latent fingerprints on paper surfaces were investigated. Under the same concentration, the effects of β-OMe, β-NO2, β-Me ninhydrin were compared through latent fingerprint developments on different papers with multiple dimensions, respectively, and their effects were also compared with ninhydrin to analyze the advantages and disadvantages. Three β-substituted ninhydrin derivatives could develop fingerprints on different papers. The effect of β-NO2 ninhydrin was slightly inferior to the others as its solution was brown at the same time the displayed fingerprint was dark brown; the effect of β-OMe, β-Me ninhydrin was equivalent to ninhydrin in many dimensions and the sensitivity was slightly higher than ninhydrin, as well as the stability of Ruhemann’s purple. The modification on β-position could change the fingerprint development effect of ninhydrin; the substitution of electron-donating groups could improve the fingerprint development effect of ninhydrin; the fluorescence performance of these compounds was not directly related to the visual effect of fingerprint display.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
An analytical method was established for determination of 5 common veterinary anesthetics (tiletamine, xylazole, ketamine, xylazine and zolazepam) in whole blood by using programmed temperature vaporizer (PTV) system combined GC-MS/MS. Those samples were dealt with salting-out-assisted liquid-liquid extraction (SALLE), introducing NaCl as salting-out regent and acetonitrile as extraction solvent. After that, the extracting solution was purified by QuEChERS nano column. Most acetonitrile in the solution were removed by PTV system before analyzing in GC-MS/MS for protection of gas chromatographic column. The multiple-reaction-monitoring (MRM) positive ion mode was selected for detection. Three pairs of characteristic ions were taken for qualitative analysis and external standard method was accepted for quantitative analysis. The method was verified well. The results showed that the LODs were 10-20 ng/mL and LOQs were 20-40 ng/mL. There were good linear relationships for all the analytes with correlation coefficients (r) not less than 0.998. At three spiked levels of 40, 400, and 2 000 ng/mL, the recoveries for 5 veterinary anesthetics in whole blood ranged from 71.61% to 119.10%. The intra-day precision and inter-day precision of the method evaluated at the concentration of three levels ranged from 0.34% to 14.81%, 4.03% to 14.87%, respectively. The developed method with broad research potential benefited its simple pretreatment, fine stability and highly sensitivity, which was applied in an actual case.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
In the process of cracking down on new types of network-related crimes, the collection of data from suspects’ mobile phones is a key part in obtaining evidence, while in actual cases, the WeChat records in the mobile phone, which have vital clues and evidence, are usually deleted. How to quickly and efficiently restore the deleted WeChat records in the suspects’ mobile phones is an urgent problem to be solved in the investigation of related cases. This paper used the latest version of the four most commonly used forensics systems to collect WeChat data twice from more than thirty models of mainstream Huawei and Apple cell phones. The data was collected directly without any operation on the mobile phone, and then the data was collected again after the old version of the operating system was upgraded. In this way, we could compare and analyze the effect of different forensic systems to restore the deleted chat records of Huawei and Apple mobile phones. This paper can provide a reference for the selection of forensic tools in the investigation of related cases.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
Palm print is one of the most important parts of dermatoglyphics and forensic science. Palm print is genetic related and also is individual unique during one’s whole life. It has played and still playing a very important role in the individual identification. In this paper 720 pairs of inked palm print samples were collected and studied. Twenty two types of papillary patterns were found and their frequency of occurrence in each areas of palm was calculated. The distribution characters of triangles in tri-radiate area and the other accompanying patterns, such as stairs-like ridges and small upside-down loop in thenar area, were analyzed. The combined patterns formed in tri-radiate, thenar and hypothenar area were summarized. The characters of palm print patterns in the three areas were also discussed according to gender and hands. The result showed that three to seven triangles could be formed in tri-radiate area of palm and the number of triangles was related closely to the type and quantity of papillary patterns appearing in this area. Ninety-six point eight seven percent of the tri-radiate prints had one to three papillary patterns, in which the upside-down loop beneath ring finger and little finger has the highest overall frequency. Eight types of single papillary patterns and ten types of double combined papillary patterns have been found in the tri-radiate area, while three types of triple combined papillary patterns have been found in this area. The total occurrence frequency of the papillary patterns in the tri-radiate area was that of male higher than female and in right hand higher than in left hand. Nine point one zero percent of the thenar palm prints had papillary patterns, in which the inner sloping loop showed the highest frequency of occurrence. Stairs-like ridges were found above all of the inner sloping loops and outer horizontal loops, while only few percentage of small upside-down loops appearing above the stairs-like ridges in thenar area. The total occurrence frequency of the papillary patterns in the thenar area was that of male higher than female and in left hand higher than in right hand. Fourteen point one seven percent of the hypothenar palm prints had papillary patterns, in which the outer sloping loop showed the highest frequency of occurrence. Eight types of single papillary patterns and three types of double combined papillary patterns have been found in the hypothenar area. The occurrence frequency of the papillary patterns in the hypothenar area was that of female higher than male and in left hand higher than in right hand. Due to the limited scope of sample collection, the statistical analysis of parameters such as the types and quantities of papillary patterns appearing in various areas of palm in the paper may not be comprehensive enough. As a result, there might be small or large deviations in the calculation of various frequency values, which will be supplemented and corrected in future research.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
Objective and accurate forensic genetic analysis results are the basis for making accurate identification opinions. With the increasing sensitivity of testing equipment and amplification kits, the pressure to prevent laboratory pollution is increasing. Among them, the contamination of PCR amplification products is the most difficult type of pollution to prevent. This research introduces an anti-pollution amplification kit, which contains 16 short tandem repeats (STR) locus, one sex identification locus (Amel) and one Y chromosome insertion deletion locus (Indel). Anti-pollution amplification kit can obtain DNA fragment containing uracil base through STR multiplex amplification, and this type of DNA fragment can be efficiently hydrolyzed by uracil DNA glycosylase (UDG enzyme) at 50℃. An additional 50℃ incubation before each new round of PCR amplification can completely eliminate the pollution threat of previous amplification products to the results. After testing, the anti-pollution amplification kit has excellent anti-pollution ability, and uracil base does not change the DNA typing results. Its detection sensitivity does not decrease; the stability of DNA product fragments does not decrease; and subsequent electrophoresis analysis is not affected. This reagent kit can effectively eliminate contamination of amplification products.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
Mycotoxins are secondary metabolites produced by phytopathogenic fungi under specific conditions. They are widely distributed in crops, and are chemically stable and highly toxic. In criminal cases, the detection of mycotoxins in biological samples can provide more accurate forensic evidence; therefore, the detection of mycotoxins in biological samples has gained great attention. In this study, common mycotoxins and their metabolites in biological samples are introduced, and pretreatment methods, such as liquid-liquid extraction, solid-phase extraction, and protein precipitation, are summarized. Detection methods, such as immunoassay, fluorescence assay, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry, were reviewed, and the future of mycotoxins and metabolites detection in biological samples were prospected with the aim of providing information on the detection of mycotoxins in the field of forensic science.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
Water-soluble poisons refer to poisons with high solubility in water, characterized by rapid absorption and high toxicity. They are easily distributed in various tissues and organs of the body through blood circulation, causing serious harm to human body. This article selected four common water-soluble poisons, including nitrite, cyanide, sodium fluoroacetate, and borax. It mainly reviewed the physicochemical properties, toxicological mechanisms, poisoning symptoms, and metabolic processes in the body of the four toxins, as well as the current developments and future trends of their detection methods form home and abroad. This article mainly aimed at providing references in forensic toxicology analysis of water-soluble poisons and investigating the causes of such suspected poisoning cases.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
Handwriting identification is a crucial aspect of forensic analysis that heavily relies on the experience of forensic handwriting examiners. Over the years, the increasing demands for accurate identification led to a growing interest in statistical methods within the field. These statistical techniques provided an objective way to quantify the characteristics of handwriting and analyzed the collected data in a reasonable manner. By employing effective statistical methods, not only can the identification conclusions obtained from handwriting analysis be supported by a strong theoretical foundation, but it also allows a deeper exploration of the intricate information hidden within the complex data. This paper aims to provide a comprehensive review of the principles, applications, and recent advancements of several widely used statistical methods in the quantification of handwriting features and the processing of feature data. These statistical methods offered valuable tools for objectively measuring various aspects of handwriting. By utilizing these techniques, forensic handwriting examiners could extract quantitative measurements that serve as valuable evidence in the identification process. In recent years, machine learning had been developed to recognize and classify handwriting patterns, improving the efficiency and accuracy of the identification process. Looking ahead, statistical methods will continue to play a vital role in the field of handwriting identification. In conclusion, the integration of statistical methods in handwriting identification had brought significant advancements to the field. These methods provided an objective and systematic approach to quantifying and analyzing the characteristics of handwriting, thereby supporting the conclusions drawn from handwriting analysis. As technology continues to evolve, it is expected that statistical methods will continue to evolve as well, leading to more accurate and efficient identification processes in the future.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
Artificial intelligence (AI) is a comprehensive new region developed by computer science, neuroscience, linguistics and other disciplines. It is an intelligent solution based on big data, machine learning and other technologies, which can improve morphological recognition ability, diagnostic efficiency and quality. With the rapid development of science and technology, AI technology has made great progress and been widely used, providing new solutions for solving various practical problems. “AI+” has been widely used in all walks of life and achieved excellent results, among which, a number of excellent research results have emerged in the field of forensic medicine. In recent years, forensic scholars at home and abroad have studied the application of AI technology in many aspects, such as postmortem interval estimation, diatom test, age and sex estimation, DNA map analysis, poison test and injury mechanism determination. The achievements have greatly promoted the progress of forensic science and demonstrated the advantages of applying AI technology to solve traditional forensic problems. This paper summarizes the literatures in recent three years, hoping to provide new ideas for the research of forensic pathology, clinic, anthropology and toxicology.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
In forensic practice, the study of intersecting fracture lines is mature and its theoretical basis is sufficient, but the study of intersecting wounds and subcutaneous hemorrhage is few relatively. Through the observation and analysis of intersecting fractures, wounds and subcutaneous hemorrhage, the author studied their respective characteristics and judgment basis. According to the actual work of the author, the relevant situation was observed and analyzed in the actual investigation process. The fracture lines at the blocked places were in a sequence, the intersecting fracture lines were formed after they were blocked, and the blocked places were probably not the point of direct action of external forces. It is possible for the closed intersecting fracture line, the obvious dislocation fracture line formed is later. Dislocation formation of intersecting wounds blocked due to traumatic edge, wound cavity, or iatrogenic intentional blocked. Subcutaneous hemorrhage that forms first is more likely to be deformed or blocked. That is to say, the blocked fracture line and wound often form later, iatrogenic intentional blocked form later, and the subcutaneous hemorrhage formed earlier is more likely to be blocked. It is of great significance to fully understand and distinguish the sequence of various injuries in order to reconstruct the case and reproduce the facts.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
In order to explain the various doubts found in the case of forensic authentication of audio recordings recorded by iPhone, this paper makes a series of experimental analysis and exploration by using the iPhone in the case and some other common iPhones. In this experiment, the recording files of iPhone12, iPhone SE, iPhone 6 and iPhone 4s were synchronized, copied, cut, replaced, cleaned, and the recording quality was modified, and the changes of file name format, sampling rate, modification date and “composition” file folder were observed. The experiment found that in the experimental iPhones, the recording file of the voice memo was only allowed to be synchronized once. The “Lossless audio” and “Compressed audio” settings in iPhone recording settings only changed the voice frequency and did not change the recording sampling rate. The experiment summarized the file name changing rules of copying voice from the above-mentioned iPhone voice memo recording list, and found that cutting and replacing operations did not change the file name format. In the experiment, the sampling rate changed only when the iPhone 12 recorded audio was replaced, and this phenomenon did not occur in other experimental operations or experiments on other iphones. The original recordings recorded on iPhones were stored in the “composition” folder, but when copying, only voice files existed on the phone, and there was no “composition” folder. The existence and content of the “Fragments” folder in the “composition” folder were related to the model of iPhones and the specific operation behavior of recording files. Therefore, the “composition” folder and the “fragment” folder could become the key inspection items for the authenticity identification of the recorded files on iphones. ITunes voice memo information had strong stability and would not change with file copying and editing. These regular understandings can provide theoretical basis and practical experience for the forensic audio authentication of more recordings recorded by iPhones.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
Recently, there have been instances of corporate financial personnel being defrauded in QQ group chats. The primary method employed by the criminals involves illegally obtaining QQ login permissions to gain control over user group operations. They then add the compromised account to a pre-set “work” group and wait for the account owner to log in. Upon logging in, the victim would find familiar contacts, such as his boss, in the pre-set group and receive instructions to transfer funds, ultimately resulting in fraud. Through our investigation and analysis of a real case, we discovered that these types of scams are spear-phishing attacks executed through the leakage of QQ account ClientKey information, supported by a corresponding QQ gray industry. This paper, using the evolution of QQ gray market as a backdrop, provides a detailed analysis of the complete technical architecture of this gray market. It presents methods for inspecting trojans that steal account information and mirrored servers, including ways to bypass the challenges posed by disguised source code settings in mirrored server images, and summarizes key evidence points. Lastly, through local co-debugging, we verified the coupling of the account-stealing trojans and mirrored servers, while also highlighting the security risks inherent in the current QQ fast login feature to a certain extent.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
This article studies the characteristics of cases involving the solo killing of boys under the age of 12 in China. It provides reference for on-site investigation and detection of such cases. A total of 173 relevant cases were collected from 22 provinces, autonomous regions, and municipalities. The observation indicators included the age of the victims, the location of the crime, the number and age of the offenders, the gender and occupation of the offenders, the relationship between the parties, the motive for the crime, the method of murder, the controlling and disposing behaviors, etc. SPSS Statistics 25 was used for statistical analysis. The statistical results showed that the average age of the victims was 5.8 years old, with indoor crime scenes accounting for 70%. Single offender cases accounted for 97%, with an average age of the offenders being 32 years old (among them, offenders aged 18-37 accounted for about 62%, and minors participating in the crime accounted for about 10%). Female offenders accounted for about 36%, while agricultural and unemployed individuals accounted for 37% and 27% respectively. About 98% of the cases were committed by acquaintances. Premeditated crimes accounted for about 64%, and mechanical asphyxiation accounted for about 40%. About 75% of the offenders did not take any special disposal measures after the crime. Through the analysis of the above cases, it was found that cases of solo killing of boys under the age of 12 in China have the following characteristics: the majorities of cases occur indoors, with single offenders being predominantly male, young, and commonly engaged in agriculture or unemployment. Female offenders have a relatively high proportion, and acquaintances are the most common relationship between the parties involved. The main motive for the crime is premeditation, and the main methods of murder are mechanical asphyxiation, sharp weapon stabbing, and blunt weapon striking. Only a small number of offenders take special disposal measures after the crime, and cases of boys aged 0 to 1 being killed alone are mostly committed by close relatives.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
Pathological fractures in children have an insidious onset, and the bone quality of the lesion site is weak, often diagnosed as pathological fracture after being subjected to external force, and usually the fracture line is located in the tumor site. Children’s pathologic fracture disability rating is relatively rare, and this kind of case is more controversial in the forensic clinical appraisal activities. Injury and disease coexistence, how to assess the disability rating and the relationship between injury and disease treatment is the difficulty of this kind of case. In the paper, the author reviewed this case from the completeness of the medical record data, the choice of imaging data, the use of DICOM files, identification of the timing of the choice, and the relationship between injuries and diseases. The key points were noted during children’s pathologic fracture identification process which serve as a reference for similar cases.
Abstract (
)
Download PDF
HTML
(
)
Knowledge map
Save
With the development of technology, more and more cases of chimerism have been found in paternity tests. At present, blood sample is the most commonly used for paternity testing, and a few institutions take oral swabs as samples. After ruling out the possibility of iatrogenic artificial chimerism and sample contamination, the presence of multiple alleles in different loci usually indicates congenital chimerism. However, if the chimera blood contains only one type of cell population, the autosomal STR typing of the blood sample will not be abnormal, and it is easy to draw a false identification conclusion that excludes relatives. This paper reports a very rare case of chimera. In this case, gene chimerism was detected only in seminal stain, and no chimerism was found in blood samples, hair and saliva spots. When blood was used for paternity test, the tested father was excluded as the biological father of the two children. However, when sperm plaques were used as samples, it was supported that the tested father was the biological father of the two children. The analysis suggests that the father is a chimera formed by the parthenogenetic division of the mother’s germ cells. Cases of chimerism, which occurs after the fusion of two fertilized eggs, have been reported only in germ cells and not in blood cells. For forensic identification, it is necessary to improve the understanding of chimerism. When the phenomenon of chimerism is suspected, the samples from different parts should be extracted and compared as far as possible.
