As soon as ChatGPT came out, it attracted widespread attention. This article takes ChatGPT as an example, briefly describes the use, characteristics and advantages of large language models, and analyzes the current controversies, ethical dilemmas and information security risks. This paper focuses on the analysis of the possible applications of large language models in crimes, and discusses the use of ChatGPT to assist in the acquisition of criminal skills, the implementation of cybercrimes, phishing attacks, and the dissemination of false information. This paper also explores the use of ChatGPT at the law enforcement fields, including serving crime fighting, crime prevention, law enforcement decision-making, and law enforcement capacity building. This paper believes that law enforcement agencies should keep an open attitude, pay close attention to the impact of the application of artificial intelligence technology on crime, represented by ChatGPT. Law enforcement agencies should strengthen research and deal with ChatGPT from both aspects of “positive” and “negative” attitude, applying new technologies to help with law enforcement activities and improve efficiency.

Simulative explosion is usable for restoring the course of involving event and reconstructing the relevant case scene. Hence, three choices of LS-PrePost-based simulative modeling were here tried about explosion with spherical charging: the keyword *LOAD_BLAST-guided, the SPH-directed and the keyword *INITIAL_VOLUME_FRACTION_GEOMETRY- led, thus having their advantages and disadvantages analyzed along with the applicable scenarios. All the simulations were conducted under the optimal load of 1 kg TNT charged into three different shapes so that the generated blast air-shock waves (represented with peak overpressure) were able to unfold their variations. The finite element software LS-PrePost was utilized to put into a verified finite-element model for the explosion simulation to carry out, with every simulation only changing the shape parameter of charging. The ANSYS\LS-DYNA was the solver to respond the discrepant ways of spherical, columnar and square charging in turn, having obtained the peak overpressure at diverse scaling distances, acquired some representative simulation data and delivered a statistical chart to compare the differences between every group of peak overpressure data. It was shown that there was a closer peak overpressure generated from the columnar charging and the spherical with the scaling distance less than or equal to 1.0 m·kg^-1/3, while that from the square charging and the spherical tending to a bigger difference. If the scaling distance was increasing, the ratio of peak overpressures almost kept stable from the columnar charging against the spherical, while that from the square charging against the spherical revealing gradually increasing and changing a lot. Evidently, shape-different charging does impact the generated shock-wave peak overpressure, deserving of no ignoring. Therefore, when investigating the charging with an actual explosive case and the consequent destroying effect, the explosion simulation should be carried out with the charging shape as close to the actual cases as possible. For exploration about the problems approaching to an explosion simulation, it is also necessary to choose the appropriate modeling way and charging setup so as to ensure the accuracy and reliability of the analysis and results.

Presently, such an increasing demand emerges for the identification of complex genetic relationships in forensic practice that requires the combination of a variety of genetic markers, e.g., STRs, X/Y specific indicators, SNPs and mitochondrial DNA. Next generation sequencing (NGS) approach is able to integrate multiple genetic markers into one detection system, excelling the traditional capillary electrophoresis (CE) technology in overcoming the cumbersome operational procedures and experimental handling. Here, a typing panel, designated as DNATyper^TMNGSPanel v1.0, was developed with enclosure of human 29 autosomal STRs, 36 Y-STRs, 32 X-STRs, 71 Y-SNPs and the whole genome of mtDNA. Its validation was implemented under the guidelines of the Scientific Working Group on DNA Analysis Methods (SWGDAM), having evaluated the items of repeatability, accuracy, consistency, sensitivity, mixture and species specificity. For the developed DNATyper^TMNGSPanel v1.0, a consistency of 99.72% was shown to the detection with CE, plus the complete identical results coming true between the genic loci shared with it and the Forenseq™ DNA Signature Prep Kit. No allelic loss occurred to the DNA template of 0.5 to 10 ng, yet the respective 2 and 9 loci being lost with the 0.25 ng and 0.125 ng of template. Regarding to the mixture of male and female substances, the mixed ratio of 2׃1 had the the female’s begun to appear allelic loss, contrasting that the mixed ratios of 9׃1, 4׃1, 2׃1 and 1׃1 brought the positive detections to 54.72%, 81.13%, 98.11% and 100%; and the mixed ratio of 1׃4 made the male’s happen to allelic loss, opposite the mixed ratios of 1׃1, 1׃2, 1׃4 and 1׃9 rendering the positive detections to 100%, 100%, 90.24% and 82.93%. The test of species specificity proved that the developed DNATyper^TMNGSPanel v1.0 hardly amplified the DNA from pig, cattle, mouse, either the cynomolgus monkey or the rhesus one. In conclusion, the developed DNATyper^TMNGSPanel v1.0 is of high detection throughput, high sensitivity and stability, accurate and repeatable typing and good ability for mixed sample to detect. Also, it can deliver the genetic information related to paternity and maternity at the same time in just a single run of test with any common biological samples, hence eligible for boosting the capability of individual identification and efficiency of consanguinity determination.

Fingerprint seals or films, made from people's real fingerprints, are at times used for related individuals to do their business conveniently, yet leaving behind the risk for violators to forge these fingerprints to seek illegal interests. At present, the fingerprint identification mainly focuses on two aspects: one is the traditional morphological comparison; the other is the emerging deep-learning recognition. Unfortunately, there is still a lack of scientific, effective, mature and stable examination methods to distinguish the genuine fingerprints from those fake ones which are often appeared with their red-ink-displayed versions on documents. In principle, genuine fingerprints definitely contain the substances transferred from their human donors, yet the fake fingerprints only contain substances from the used ink. Therefore, an identification method was here designed to discern the genuine and fake fingerprints displayed with red ink on documents, and verified of its scientificity and effectiveness through experiments. Specifically, the fake fingerprints were made via photosensitive fingerprint seals imbibing red ink and then pressing against the paper carriers, with the genuine fingerprints being prepared by relevant fingers directly pressing against red inkpad and then imprinting onto paper carriers. Both the genuine and fake fingerprints were placed for designated durations of time. The transfer medium was used to convey the red fingerprints (both geunine and fake), and treated with ninhydrin operation under two modes: one, developing the fingerprints through reaction of fingerprint-harbored substances (if present) with the fingerprint developer along with the transferring process; the other, first having the fingerprints transferred onto the medium previously soaked with related working fluids and then developed via fingerprint developer. Consequently, the transferred fingerprints were observed of their changes before and after displaying treatment (whether the Ruhemann's purple appeared on the transfer medium). The results showed that: 1) two modes were both able to successfully transfer the fingerprint substances and develop the fingerprint on the transfer medium, demonstrating that genuine fingerprint did result in the Ruhemann's purple appearing while none with the fake fingerprint; 2) the mode two displayed better processing effect than the mode one; 3) the mode two successfully transferred the fingerprints left for 1, 2, 7, 15 and 30 days, and had Ruhemann's purple emerged when ninhydrin treated to the relevant medium transferred from genuine fingerprint while none from the fake fingerprints. Evidently, there are differences in the distribution of componential substances between genuine and fake fingerprints. A method has been herewith established to identify genuine and fake fingerprints on documents based on the principle of fingerprint substance transferring, verifying that the identification can be realized with the fingerprints retained for legacy time of 1, 2, 7, 15 and 30 days.

The mixed stain of seminal and vaginal fluid is one of the important evidential materials in sexual assault cases, a crucial item in forensic biological examination, too. The vital role will be played when the sperm cell DNA is separated and extracted from the mixed stain and matched to the criminal suspect, resulting in the identification or exclusion of criminal suspects and successful unravelment of the involving case. Forensic scientists have until present established a variety of methods for separating sperm DNA from the mixed stains in their endeavor to meet the requirements of DNA detection and solve the specific problems and difficulties from actual cases. This review summarizes the relevant methods at the two levels of cell and DNA about their core gists, advantages, disadvantages and applicability, focusing on the new research progress home and abroad in recent years and carrying out overview and prospect with combination into the practical forensic applicability and developability.

Fingerprint, one kind of the most important forensic evidence, is capable of having an individual identified. Therefore, it has played a crucial role in a police investigations and court litigation since it was admitted under jurisprudence. Regarding the verdict of fingerprint identification, there are currently only three propositions in China: recognition, exclusion, and inconclusiveness. Presumably, such handling roots its basis on the experience and practical situation of China's crime prevention and court processing hitherto, yet having caused abandonment or unusedness of amount-huge fingerprints collected of less than 8 minutiae from crime scenes due to their disqualification to the requirements of source threshold for fingerprint identification. However, these fingerprints are significant for police investigation and court processing. Thus, a probabilistic approach was described here with mathematic modeling to count minutiae by the related fingerprint image divided into fan-shaped sectors. Based on the statistics of 15 million fingerprint images, a function of probability density was fitted into fingerprint minutiae of all fan-shaped sectors and then modified under Bayesian Information Criteria, plus the addition of noises. Consequently, a probability was acquired towards identity recognition about a fingerprint under scrutiny. Through a trial of several examples, the results showed that the matching probability of fingerprint pairs was positively correlated to the quantity and stability of the analyzed minutiae yet negatively to the incidence of minutiae occurring inside the fan-shaped sectors. This study provided a novel attempt to rediscover the evidential value of those ‘useless fingerprints' displaying no sufficient details for identification but frequently found at crime scenes. Such an approach should be a crucial step for fingerprint identification from quality to quantity analysis, having significant potential to identify a criminal in combination with the quantifying applications of other forensic evidence.

Fingerprint, among the so-called “king of evidence”, always plays its crucial role in solving relevant cases. Therefore, fingerprint patterns are paid of incessant attentions from dactylgraphers. Here, the regularity of chiral symmetry of human ten-digit fingerprints was to explore with purpose to provide more reference information for fingerprint analysis and supply basic statistical data for investigation of fingerprint heredity. With collection of the fingerprint cards of 500 males' all ten fingers, 5000 fingerprints were consequently divided into 10 types of patterns according to six-step taxonomy. The symmetry of each fingerprint pattern was recorded about the name-same fingers from every ten-digit fingerprint card, together with the counts taken of the symmetrical samples, the isoform asymmetric ones and those simultaneously appearing on the name-same fingers of each pattern. SPSS software was chosen to analyze the correlation between pattern occurrence and the number of those showing symmetry. All the patterns were shown of higher symmetry rate with the ten-digit fingerprints, having particularly the arch pattern indicated of proneness to symmetry with thumb while the loop and/or whorl patterns more symmetrical with the little finger. Correlation analysis showed that the strongest correlativity linked to the index, little and/or middle finger while a relatively weak correlativity to the ring finger that was still demonstrated of high in terms of coefficient. In conclusion, good fingerprint-pattern symmetry emerges with the name-same fingers of left and right hand. The regularity of fingerprint-pattern symmetry revealed here should be able to provide more information in the case of fingerprints difficult to identify. Additionally, the chiral symmetry of fingerprint pattern may have its value in genetics and racial ascendancy.

Mobile smart devices, e.g., the mobile phones, are always built with the acoustic and optical sensors representing their rapid developing and wide applying mainstream technologies so that the relevant image authentication has got to comparatively mature and comprehensive solutions about those involving metadata, imaging artifices, processing signs and image signals. However, the ever-personalized camera programs are available and popular in mobile phones, bringing in problems occurring for forensic authentication of images taken under related handling. Here, forensic authentication was put into the images imposed by watermarking camera programs set up with mobile phones. Two popular watermarking camera programs (developed by Shanghai-based Tencent Technology Co., Ltd. and Beijing Xiaohei Technology Co., Ltd.) were used to explore the feasible examination materials and methods for the purpsoe of forensic authentication. Through scrutiny into the features of the original images imposed by watermarking cameras and the conditions of watermarking, an exampling case was carried out on how to undertake the concrete examination process of such the kind of forensic image authentication and have the effectiveness verified. Evidently, the file attributes and metadata information did play an important role for such an authentication although some differences were present from the traditional examination materials. For example, the “Photoshop” information in the metadata of images hints the existence of editing operation traditionally, yet being taken as a normal phenomenon and reasonable presence for the images imposed by watermarking camera programs. Therefore, in order to achieve the objective and scientific opinions with examination, much attention should be paid to the characteristics of mobile phones’ operating systems and watermarking camera programs, the two key materials for forensic authentication of images imposed by personalized camera programs built in mobile phones.

Fingerprint identification tends to be much attention paid on more detailed and specific features of fingerprint, e.g., the level 3 feature so that the further correlative evidence can be obtained against the involving suspect. Besides, the influential factors are gathering to link with the quality of fingerprints from crime scenes, the changes with identification standards and other challenges about real cases, having brought fingerprint examiners to shift their focus from macroscopic characteristics to those minute features. Moreover, the continuous progress of fingerprint development and extraction technology is gradually making the level 3 features able to recognize and identify, leaving such features to become an active research target. The done researches mainly emphasize on the basis about how the level 3 features play a role for fingerprint identification and their applicable conditions. Here, a comprehensive and in-depth analysis and introduction was carried out into the current status of the level 3 features' researching home and abroad with four aspects: basic attributes, reliability, automatic identification and identification attributes. Through an explicit description with the research process, a discussion was finally conducted on the prospect of level 3 features' researching, purposing to provide some references for the level 3 features to better integrate into fingerprint evidence and evaluation.

Immobile phone is presently of less attention for electronic evidence collection because it is commonly thought to be no storage function, leaving it little significance for evidence obtainment. However, the fact is that not all immobile phones aren’t able to store information. For immobile phones equipped with storage chip, some valuable information (e.g., calling details) can still be extracted from them. Actually, immobile phones are among the criminal tools widely utilized by culprits in current telecom network crime. Therefore, the relevant calling information recorded in the case-involved immobile phones will play an important role for the case to solve. Here, electronic forensics were carried out about extracting and analyzing the calling information recorded in storage chip of the case-involving immobile phone. From the disassembled immobile phone, the memory chip was taken out to have the physical image ghosted so that the calling information data were capable of being extracted out of the ghosted image with WinHex software. The program was written by Python to sort out and display the original data about the ghosted image, together with deep excavation into the potential calling rules, calling duration and other information. Consequently, immobile phone should not be ignored in investigation of telecom network crimes, and the Python program is indeed a good helper for extracting electronic evidential data out from immobile phone.

Fingerprint identification relates to relevant standards, involving specific features, developing technologies and the ever-exerting computer-based fingerprint automatic identification system (AFIS). For fingerprint features, those traditional level-2 ones play their roles in increasing juxtaposition to the level-3 ones with which the systematic basic researches have been already carried out on the related pores about their short-term tissue stability or the trackable others. Besides, the traditional level-2 features have been further subdivided and classified into some rare and more-detailed types. About AFIS, the existing version is facing many technical bottlenecks owing to its expansion of capacity and the recognition of numerous microscopic characteristics. Actually, the AFIS now available in China can only standardize the level-2 features, unable to effectively identify and compare those of level-3's. Even worse, the continuous enrollment of the fingerprint samples is causing the comparison accuracy of AFIS to decline, resulting in occurrence of the close-yet-nonmatched fingerprints which are indicative of two fingerprints, highly similar yet not homologous, commonly appearing more in the triangle zones. Such fingerprints are potential to cause a certain cognitive risk to identify incomplete fingerprints. Promisingly, a fusion algorithm has been developed about fingerprint's level-2 and level-3 features, realizing new functions such as the in vivo fingerprint detection. Furthermore, the rapid development of computer technology and establishment of fingerprint databases have made machine learning fulfilled to apply into fingerprint identification in academic and actual practice home and abroad. Usually, the machine learning takes large-scale fingerprint data as models for training and verification through different systems so that a likelihood ratio evaluation model is therewith developed to deliver the probability about fingerprint identity, hence bringing forth the fingerprint identification conclusion from absolute to relative. This paper summarizes the latest achievements related to the above aspects, putting forward the problems and envisioning the prospects for future progress trend regarding to fingerprint identification.

In all kinds of shooting incidents, it is more common for ricochet to cause casualties or property losses. At the scene of ricochet shooting, the bullet head and relevant marks have been deformed to varying degrees, affecting the trace inspection and on-site ballistic analysis. This paper investigates and analyzes the jumping bullet scene caused by a police officer’s 92 pistol shooting in the process of law enforcement, introduces the quantitative characteristics of the jumping bullet trace into the gunshot jumping bullet analysis, and tests the size and morphological characteristics of the jumping bullet point trace and the bullet deformation surface trace. During the process of jumping bullet shooting, the bullet head penetrated multiple wooden objects. By measuring the size and distance of the firing entrance and exit traces and the jumping points on the relevant objects, the incidence angle and the rebound angle of the jumping bullets are accurately calculated. The ballistic analysis is carried out in combination with the site layout and distance, and the location of the firing points and firing angle are restored, providing a scientific basis for ascertaining the nature of the case. This paper provides a reference for the investigation, evidence collection, and event characterization of such incidents.

In fire scene, the discovery and extraction of evidential fingerprints are valuable for identifying the relevant suspects or responsible persons. However, the fire scene is usually destructive and complex, resulting in the display of fingerprint there being difficult. Overseas scholars have explored the applicability of displaying reagents and ash removal for fire-baked fingerprint to develop. Currently, there is a lack of relevant researches on portable instruments to extract the on-site fingerprints at fire scene. In addition, few researches have seemed to conduct about the effectiveness of fingerprint display after long-duration exposure to high temperature in fire scene. Targeting at this situation, an experimental research was carried out, with the quartz resistant to high temperature being selected as the fingerprint carrier to explore portable instruments to recover the fingerprints survived at fire scene. The fingerprint samples were prepared under high-temperature conditions simulating the scene of a fire. Two methods, the optical nondestructive exposure and "502"glue fuming, were used to explore the impact of high temperature on fingerprint display. The results showed that the longer the baking time at the same temperature/the higher the baking temperature at the same time, the more serious the fingerprint damage. Optical nondestructive exposure can obtain good extraction results for fingerprints baked below 500 °C for about 10 minutes, or below 400 °C for 20-30 minutes, yet appearing worse presentation than the “502” glue fuming under all experimental conditions. Therefore, this research can provide reference for suitable choices (e.g., the two methods adopted in this research) to extract and display the evidential fingerprints in fire scene.

Synthetic cannabinoids are of hallucinogenic effect equivalent to or even stronger than that of cannabis, being listed under the first batch of new psychoactive substances controlled in China. There are many kinds of synthetic cannabinoids, among which MDMB-4en-PINACA and ADB-BUTINACA are recently the two ones of most active alkyl formyl indazole in the market. Such two synthetic cannabinoids have presumably not been reported about their metabolic researches in China. Thus, both the MDMB-4en-PINACA and ADB-BUTINACA were here probed into their metabolites from the blood and liver of rats. With 12 SD rats randomly divided into two equal groups: one for MDMB-4en-PINACA and the other for ADB-BUTINACA, each rat was fasted for 12 h and then intraperitoneally administered once by weight as per 1.0 mg/kg along with the two groups leaving one rat taken as the control that was not injected of drug yet executed just before administration. The remaining five rats in each group administered of drug were respectively killed at 5, 15, 30, 60 and 120 min after drug injection, having their blood and liver tissues received and successively analyzed into high performance liquid chromatography quadrupole time of flight mass spectrometry (HPLC-QTOF). The results showed that the experimental rats had MDMB-4en-PINACA metabolized into corresponding metabolites through double bond oxidative carboxylation, ester hydrolysis, 4-depentenylation and hydroxylation, with ADB-BUTINACA being metabolized through hydrolysis, 4-dealkylation, 4-butyl hydroxylation and hydroxylation. According to the response intensity of components in blood and liver tissue of rat, MDMB-4en-PINACA mainly converted into its metabolites from pentenyl oxidative hydroxylation (No. M6), pentenyl oxidative carboxylation (No. M7), methyl butyrate hydrolysis (No. M2) and further hydroxylation (No. M3/M4/M5) and dealkylation (No. M1), demonstrating its metabolic markers as M1 and M2. ADB-BUTINACA mainly turned into its metabolites from debutylation (No. A1), formamide hydrolysis (No. A2), butyl carboxylation (No. A3) and butyl hydroxylation (No. A4), with its metabolic markers being as A1 and A2.

Objective Evidential cartridges can provide scientific basis with their chemical composition analysis into the investigation of gun-related cases. Therefore, an experiment is here to carry out for quickly distinguishing different bullets and providing key information on inferring discrepant bullets through the element composition of sampling cartridges to probe. Methods 53 producer-different and specification-various sampling cartridges were collected with their manufacuring at the unlike batches during 1958~2019. Major element composition was to determine into the different components (i.e., lead core inside bullet, bullet jacket and cartridge case) of the sampling cartridges, delivering results through the test with scanning electron microscopy and energy dispersive X-ray (SEM-EDX). Results Most bullets were shown of made of pure lead, with some of later-produced batches being of lead-antimony alloy, two earlier-produced batches of iron warhead. Although there were no obvious regular features for either the jackets of six 5.6mm sporting rifle's cartridges or the shells of four samples made from factory 791, all the other analyzed jackets and shells were made with three types of Cu/Zn alloy, revealing the Cu content ranging between 83.7%-84.7%, 87.6%-90.6% and 67.0%-69.8%, respectively. The materials used in the jacket and shell from the model- and manufacturer-same samples remained consistent over time, contrasting to the significant differences with both the model-same yet manufacturer-different samples and the model-different yet manufacturer-same ones. Over the past 60 years, the samples produced from factory 121 had their bullet jacket and shell both made of Cu/Zn alloy, with the Cu accounting for 87.6%-90.6% of jacket and 67.0-69.8% of shell, suggesting that these two types of Cu/Zn alloy were the common raw materials used with the factory. Four shells of sampling cartridges produced from factory 791 were made of Fe/Mn alloy with Mn accounting for 0.7-0.9%, however, the other manufacturers selected for this experiment hadn't been found to adopt the Fe/Mn alloy. Conclusion Element composition and analysis can be used as choice to identify the kind of bullets through determination of the materials of their components.

Two cases were here reported about abnormal elevation of cadmium concentration in postmortem heart blood of victims who died from non-cadmium poisoning. One dead showed her heart blood was 200-fold higher of cadmium concentration than the upper limit of healthy living people, with the other one demonstrating his 40-fold higher. The autopsy also revealed that different body parts were of discrepant blood cadmium concentration, with tissues being within normal range. Observations were further made about cadmium concentration in venous blood from 100 living people and heart blood from 50 non-cadmium poisoning victims. It was found that the 100 living people were all less than 5ng/mL of cadmium concentration in venous blood, and the 50 non-cadmium poisoning victims had the raised heart cadmium concentrations. There were 20% samples appearing their postmortem blood cadmium concentrations rose to 10 times more than the upper limit of normal, with some even reaching up to nearly 100 times higher. The elevated cadmium concentration of postmortem blood may result from the postmortem redistribution and diffusion of cadmium stored in tissues, e.g., liver, kidney. Thus, a suggestion should be here put that postmortem blood cadmium concentration must be not taken as the only diagnostic indicator for identifying cadmium poisoning but combined with other sample tests and life track survey.

A novel way has been here developed for latent fingerprint to detect through the hierarchical nano-structural powders of VO₂ (vanadium dioxide). Such the innovative nano powders were synthesized from a one-step solvothermal reaction with the raw materials of vanadium acetylacetone and hydrogen peroxide, successively having them characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The synthesized VO₂ powders were of blue color, high purity and uniform morphology with submicro-spherical structure consisted of nanorods. The diameter of the submicro-spheres was about 450~650 nm. The so-prepared VO₂ powders were dusted onto different surfaces where to reveal the collected sweat and oily latent fingerprints that were compared of their development against the traditional powders. Such the nano powders brought the latent fingerprints to turn up their visions of high contrast, good definition and coherence that the fingerprints' detail features were shown remarkable, which can be attributed to the high selectivity and sensitivity of the VO₂ powders to the fingerprint-harbored residues. Compared with the traditional powders, the VO₂ hierarchical nano-structures developed better definition of latent fingerprints on glass slide and transparent plastic cup than did gold/silver/magnetic powder, and so did they on aluminum foil than gold/silver powder as it was deemed of their specific structure to play effect. In general, the smaller and more regular the size and shape of the VO₂ nano-particle, the stronger the interaction force between the particles and fingerprint-harbored residues (water, grease, etc.). The VO₂ hierarchical nano-structures demonstrated of not only characteristic of strong adsorption of nanostructured powders but also avoiding the agglomeration of nanoparticles and reducing the harm of inhaling nanopowders during operation. Moreover, their uniform spherical morphology was proved of more likely interacting with fingerprint-harbored residues. Conclusively, the fabrication for VO₂ hierarchical nano-structures is facile, low-cost and no impurity of the prepared products. Sweat and/or oily latent fingerprints can be effectively developd on both nonporous and porous surfaces using the VO₂ hierarchical nano-structures, showing themselves of better definition on glass slide, transparent plastic cup and aluminum foil than using traditional powders.

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.

Objective To provide a theoretical basis for examination of mobile phone's recording quality that is important for correct opinion to deliver in the forensic voiceprint identification of voice samples from the ubiquitous mobile phone calls. Methods A quantitative standard was proposed for evaluation of the recorded samples that were obtained from the tested mobile phones and generation-various telecom networks. The standard, rooting on the basis of mainstream identification equipment, was analyzed into the quantity and digital values of formant in voiceprint spectrogram, fundamental frequency parameters, regional average spectrum and implemented voiceprint comparison test. Results The test results showed that certain differences existed with the recording quality under different conditions, having caused definite influence on voiceprint identification, yet at a non-essential extent. Conclusion For voice identity authentication, the influence should be considered of recording quality differences on identification of the recorded samples from different mobile phones and telecom networks, therewith evaluated and overcome during identification.

There is an increasing trend for cases relating to death from diphenidol overdosing. In order to have the knowledge and identification ability improved with forensic examiners on the death caused from diphenidol poisoning, such a case of death was here reported. Combined with the relevant literature at home and abroad, a summarization was made about the characteristic corpse phenomenon of this kind of cases, revealing that rigor mortis appears early and strong with the death from diphenidol poisoning. Due to the unavailability of our knowledge regarding with the standard data on the toxic and lethal dose of diphenidol, a scrutiny was put into literature review on the death from diphenidol poisoning, hence having the expatiation aggregated about diphenidol content in the heart blood of corpses. Forensic identifiers should pay attention to the examination of diphenidol in addition to the tetramine and other poisons when encountering cadavers emerging into status of early and strong rigor mortis.

Dental individual identification is one of the important elements of the forensic individual identification system. It has the advantages of low cost of identification and long storage time of samples. Over the past decade, dental implants have become a very common procedure due to the low risk and falling prices. Implant-specific morphological features also provide available individual identification indicators for dental identification. The increased awareness of personal health care and the digitization of dental records have provided support for the development of dental identification in China. A murder case involving a highly decomposition unknown deceased was reported in this article. Due to the failure of facial recognition and DNA comparison, the forensic doctor evaluated the shape of the implant and determined the fixed batch number, locked the scope of the hospital where the deceased was treated, and compared the medical records to finally identify the victim. The paper also related the characteristics of dental implants, the unique advantages of dental implants in individual identification, and the methods of individual identification by dental implants to promote practical application in crime investigation.

The mixed stain of seminal and vaginal substances is significant evidence commonly found in sexual assault cases. How to isolate the involved perpetrator’s sperm and obtain its STR profiles is always the key to solving the relevant issue and the task any forensic DNA laboratory has to tackle. Many techniques have been invented to deal with the mixed stain, but the mainstream choice presently used in domestic laboratories is the differential lysis or its modified version. Although the methods mentioned above are of simple principle and low cost, they have still tended to bear some disadvantages that are difficult to overcome, e.g., long time-consuming, many processing steps, complex operation, low degree of automation, and difficulty in getting a single male STR genotyping in the case of entanglement with many female components. Microfluidic chips, an ever-developing technology based on different principles, have been innovated and used for capturing sperm in forensic cases. Compared with the traditional methods, microfluidic chips assume their advantages as the following rough aspects: less sample consumption; rapid high-throughput extraction, greater portability, great integrative and automotive potential; increased concentration and purity of isolated spermatozoa in the final product. Currently, there are five different types of microfluidic chips applied for separating sperm from the mixed stain of seminal and vaginal substances: one relying on different sediment velocities and adherence properties that utilize hydrodynamic filtration and pinched flow fractionation, one taking acoustic differential extraction, one basing on dielectrophoresis, and the SLeX-carbohydrate microarrays. Microfluidic chips were summarized here based on the difference in the involved two cells’ physical characteristics and ligand-specific combination according to separation mechanism, with an overview being carried out about the development of each type of microfluidic chips-the technical principle, latest progress, advantages and disadvantages, coming-up research direction, and lastly a brief comparison among the chips discussed. The continuous improvement of related technologies will be definite to launch such microfluidic chips of small size, fast response, and stable output effect that are potentially widely applied for various levels of forensic DNA laboratories to dispose mixed stains from cases.

An introduction was put here about a method to concatenate serial cases of printing counterfeit banknote by a case-involved color laser-jet copier which had thus become a basis for tracing the source of the case-related counterfeit banknote. Presently, the counterfeit banknotes are ordinarily made from copying the genuine banknotes, hence rendering them having such different serial numbers and graphical details that are unable to rely on to accurately link different cases. Dependently, the color laser-jet copiers that criminals mostly use to make their counterfeit banknotes leave a resort for investigation to deploy because the color laser-jet copiers can have their individual tracking codes printed on the counterfeit banknotes. Therefore, from the stable and specific tracking codes that are characteristic of different color laser-jet copiers, the counterfeit banknotes can be analyzed and utilized into concatenating serial cases of the kind.

The importance of digital images as evidence in judicial proceedings has become increasingly significant. The issue of traceability and forensics of digital images based on smartphones has attracted widespread attention from scholars at home and aboard. It is a new requirement and direction in the field of forensic science following the authenticity, originality and integrity of digital images. This paper mainly focuses on the digital image traceability and forensics of smartphones from four aspects. Firstly, the traceability technology and traceability characteristics of smartphone devices are introduced. In particular, smartphones have front and rear cameras, complex image processing modules and extensive transmission in social media. Therefore, the research on the traceability of smartphone devices has important practical application significance, and it is also challenging. Secondly, combined with the research situation at home and abroad in recent years, this paper introduces the research progress of smartphone device traceability from the perspectives of deep learning-based, image characteristics and image formation conditions. At present, deep learning-based traceability methods have made good progress and achieved good results on experimental datasets. Thirdly, this paper introduces 9 datasets in detail, including original images and processed images, which are convenient for readers to apply and refer to according to their own research content. The VISION dataset is an image library about smartphones established earlier, including original images, images downloaded from social media and images of different quality. It is the earliest and widely used dataset in the field of smartphone device traceability. The dataset built by Zhang Yongsheng is specially used for smartphone image traceability, which is the largest smartphone digital image dataset publicly available in China. It involves many devices, scenes and quantities, including images and videos, and the images are stored in the default way. Finally, this paper puts forward suggestions on smartphone device traceability research, including theoretical research and data set establishment. This article is expected to provide ideas and reference for the theoretical research and practical application in the field of forensic science.

A survey was here carried out about high-falling cases so that the influential factors were able to explore on the time spent with the cases' scenes, purposing to provide a theoretical and practical basis for rapid investigation into the scenes of involving cases. The high-falling cases that occurred in the selected district from June 1st, 2014 to May 31th, 2018, were collected and analyzed statistically. In total, 318 pieces of such cases were reviewed, having them kept into groups with the victims' gender and age, locations where cases happened, heights of high-falling, time spent on scene investigation of each case. Statistical analysis was respectively tested with Student t and Chi sqare about the distribution of time spent on the investigation from cases of every group mentioned above, putting the received two test results into comparison. Subsequently, the regression equation published in earlier literature was verified into the cases to estimate the falling height based on the facture degree of skull and extremity bones. Concerning the surveyed cases, suicide was the most common type, acconting for 89.0%, and occurred most in residential area. A mass of scenes were spent within 60 minutes on their investigation, acconting for 78.8% of all the cases. There were older victims in residential and hospital areas than work and other places although no significant difference was correlated with the age of victims who took off from different floors. The lower falling heights were shown at work-related sites than the rest. More time usually took on inspecting those high-falling cases at areas related to work or high floors (10 storeys and above). No significant difference was found of the spent time relating to victims' gender or cases' genre/kind. The verified regression equation performed its effective accuracy up to 75% as it had been applied into 12 practical cases. Accordingly, the falling height would be estimated more accurately if helping hands, e.g., the here-adopted regression equation, can be relied to link the corpse damage with falling height. Consequently, the time spent on scene investigation of high-falling cases will be reduced potently even on the cases occurring to high floor, hence bringing the rapid investigation into success.

Human intestinal tract accommodates the most varieties and quantity of microbes in human body, establishing the colonies of bacteria, viruses, fungi, archaea and eukaryotes that have come into being the so-called human gut microbiome (HGM). Evidently, HGM is characteristic of enormous amount of microbes, long-duration stability and liability of individual specificity, hence making it promising to arise as a novel biomarker for forensic personal identification. Factually, the explosion of microbiomics research occurred along with the availablity of high-throughput sequencing in the last decade so that the resulting novel discoveries and technologies inspired forensic scientists to seek the adequacy of practical utilization. This article tried to expatiate the characteristics of HGM and microbial molecular markers like 16S rRNA gene and internal transcribed spacer (ITS), illustrate the metagenomics sequencing and detection methods for common bacteria, viruses, fungi, archaea and eukaryotes, consequently having HGM reviewed about its research progress in relations to individual characteristics of gender, body mass index, diet, age, geographic location, race and disease. The applicable potential was therefore analyzed for HGM to play role into personal characterization and even the individual identification. Some references ought to be provided for the interested investigators.

More STR-locus enclosure is beneficial and favorable for forensic genetics to select an STR testing kit. Thus, such a purpose-oriented STR multiplex amplification system was here to establish with a combination of 39 autosomal STR loci and the Amelogenin dyed by 9-color fluorescent substances attaching to their primers, along with its forensic value being validated about the practical application including the DNA samples difficult to handle. Based on the recommended criteria for core locus/loci among Chinese populations and actual case requirements, the candidate STR loci were screened over their eligibility, together with the primers being designed. Nine-color fluorescent dyes were used to label the relevant primers. Then, purpose-different various PCR reactions and optimization process were performed to have the STR multiplex amplification system constructed. Sequentially, validation experiments were carried out into the newly-constructed system to evaluate its sensitivity, species specificity, stability and other crucial indicators including the ability to profile the STR genotypes of the samples from real cases. Therefore, a 9-color fluorescent multiplex STR amplification system was successfuly constructed, containing 39 autosomal STR loci and the Amelogenin (28 loci<300 bp). The system was validated of being well-balanced with a sensitivity of 0.125 ng and tolerance to commonly-met PCR inhibitors, the minimum ratio of distinguishing two-gender mixture being 1׃4, and suitability for testing different types of case samples. The system also demonstrated its profiling STR-locus genotypes were truly consistent with those obtained from the commercial kits of same kind. Moreover, the system was proved of fine species specificity. As presumably the first time till present of adopting 9-color fluorescent labeling design, the system has enclosed more loci into one single test, hence attaining large efficiency. Essentially, the system is mainly composed of miniSTR, therewith making it good at detection of trace and degraded DNA samples.

Objective To explore a method for aquatic decomposition scoring to estimate postmortem submersion interval (PMSI) and have its effect evaluated. Methods PMSI-known totaling 65 cases were collected from our past work in recent years, having each case obtained of its total aquatic decomposition score (TADS) with a new designed decomposition scoring algorithm. The relationship was explored between TADS and PMSI through statistical approach, rendering a regression equation. Results PMSI was positively correlated with TADS (R²=0.63, P<0.001). With log conversion of PMSI, the regression equation was established as lgPMSI=0.191+0.045TADS (R²=0.668, P<0.001). Conclusion Aquatic decomposition scoring is capable of effectively estimating PMSI.

People are pursuing quality of life higher and higher, bringing forth the ever-growing demand for healthcare food. Driven by interests, some healthcare-food enterprises even add illegal drugs like sildenafil (categorized to the PDE-5i described below) into their products, posing a serious threat to the health and life safety of consumers. State Council’s Office of the Food Safety Committee issued “Notice on further strengthening supervision into quality and safety of healthcare foods”, requiring severe crack-down on those illegal behaviors and protection to the health of consumers. Therefore, the Office of State Food and Drug Administration announced “List of substances potential of illegally added into healthcare foods (first batch)” in 2012, concluding the products that claim to be functional of relieving physical fatigue (anti-fatigue) and enhancing immunity (modulating immunity) may be illegally adulterated with the substances of red denafil, vardenafil, hydroxyhomosildenafil, sildenafil, homosildenafil, aminotadalafil, tadalafil, thiophanate and the like. Accordingly, rapid and accurate detection of the drugs illegally added into healthcare food is of great significance to keep and sustain the normal operation of healthcare food market and effectively prevent and combat against crimes involving with food and drug. Phosphodiesterase type 5 (PDE-5) is a key factor in the hydrolysis of intracellular cyclic guanosine phosphate (cGMP) in vivo, participating in regulating vascular tension, transmitting visual signals and controlling energy metabolism. Phosphodiesterase type 5 inhibitor (PDE-5i), a class of drugs that selectively inhibit phosphodiesterase activity, can play role in improving erectile dysfunction, treating pulmonary hypertension and other diseases, hence making it widely used in clinical practice. At times, PDE-5i-analogous drugs have been illegally added into healthcare food under the guise of health effect. A review was here made about the common methods for detecting the illegally-added phosphodiesterase-5 inhibitors (PDE-5i) and analogues in healthcare food, having enumerated physical and chemical rapid screening, enzyme-linked immunosorbent assay (ELISA), gold immunochromatography assay (GICA), near infrared spectrometry (NIRS), surface enhanced Raman spectroscopy (SERS), ion mobility spectrometry (IMS), thin layer chromatography (TLC), high performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). With introduction to the characteristics of each method indicated above, this article should be of providing technical support and reference for market regulating authorities and public security law enforcers to crack down on crimes about food and drug.