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 Table of Contents  
Year : 2016  |  Volume : 2  |  Issue : 1  |  Page : 22-27

The Hot Issues and Future Direction of Forensic Document Examination in China

China University of Political Science and Law, Key Laboratory of Evidence Science, Ministry of Education, Beijing; Collaborative Innovation Center of Judicial Civilization, China

Date of Web Publication3-Feb-2016

Correspondence Address:
Bing Li
No. 26, Houtunnan Road, Qinghexiaoying, Haidian District, Beijing 100192
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2349-5014.170619

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The domain of forensic document examination consists of a variety of professional tasks related to the history and preliminary of questioned documents. The wide area of tasks implemented by forensic document examiners includes the skill to identify the authorship of handwriting and signature; discriminate among genuine, imitated, or disguised handwriting; to examine and analyze components of inks, papers, and other materials connected with documents; and other highly skilled analyses based on specialized technique. The field of handwriting examination is tightly related to empirical knowledge and practical experience. Handwriting is usually thought to be behavioral activities that are identifiable due to the appearance of features and characteristics within the writing. When we assess these features we universally analyze them in two aspects: Both quality and quantity of writing. As mentioned above, the evaluation of quality and quantity is performed by forensic document examiners. The problem is how to conduct this kind of evaluation related to empirical knowledge and experience. There is not consistent answer yet, although many researchers devote themselves to explore in this hot issue, such as mathematical methods applied in handwriting analysis. In this article, several mathematical methods applied to forensic document field are deciphered in domestic perspective of China. In the digital age, we all inevitably deal with problems with the help of computer or computer technology. We also pay close attention to the computer technique assistant in the field of forensic document examination. Standards or criteria of forensic document examination are still hot issues in China. Although we established a few standards or criterion based on requires of practice, it is also a lack of standards or criterion associated to trainees and continuing education in view of practitioners. At the end of this article, the author intends to discuss a piece of a challenge to forensic document examination, which are also universal issues abroad. Those who are critical of the current state of knowledge in this area argue that members of the judiciary have failed to sufficiently address the shortcomings of the forensic document evidence proffered in criminal trials. Specifically, critics of forensic document examination argue that little valuable wording exists in the report to support the validity and reliability of the methodology and findings of forensic document examination.

Keywords: China, forensic document examination, future direction, hot issues

How to cite this article:
Li B. The Hot Issues and Future Direction of Forensic Document Examination in China. J Forensic Sci Med 2016;2:22-7

How to cite this URL:
Li B. The Hot Issues and Future Direction of Forensic Document Examination in China. J Forensic Sci Med [serial online] 2016 [cited 2022 Dec 7];2:22-7. Available from: https://www.jfsmonline.com/text.asp?2016/2/1/22/170619

  Introduction Top

It has been 60 years since the field of forensic document examination became an independent discipline. During this period, the content of the discipline was constantly enriched, and research gradually improved; further, the working staff also got an expanded development. Facing our own conditions, we had made great achievements in 60 years while took a century in other countries. Owing to the function of applying new techniques into document examination had long been took into account, the modernization of hi-tech forensic technology has resulted in rapid progress in developed countries, especially the utilization of informatics, system analysis engineering, computer technique, artificial intelligence, etc. All the technologies mentioned above have significantly promoted the modernization of the field of forensic document examination.

At the turn of the century, owing to rapid progress in modern science and technology, the field of forensic document examination in China achieved further growth. Mathematical methods came to be used to reveal principles of test objects and identify their formation processes with the ultimate goal of establishing a mathematical model. In addition, computer technology systematically combined with qualitative and quantitative analysis was applied to forensic document examination. As is expected, researchers have constantly tried to establish new test methods using state-of-the-art science and technology. Following are a few examples of forensic document examination methods: Infrared absorption - fluorescence inspection is applied to altered and faded documents for identification. Electrostatic detection apparatus (ESDA), which is used for identification of indentations - ESDA is a specialized piece of equipment commonly used for questioned document examination in order to reveal indentations or impressions in paper that may otherwise go unnoticed. Its main advantage is that it is a nondestructive technique. Thus, it allows further tests to be carried out.

Accordingly, it is evident that major developments and technologies in the forensic document examination are progressing in the direction of computerization, quantization, validity, and reliability.

  Handwriting Examination Top

Overview of handwriting examination

Continuing interest in quality assurance concerns again follows the traditional fields of signature examination, simulated writing, foreign writings, etc. However, the main area of change has been in the debates surrounding the interpretation and presentation of this evidence type. Further developments have continued surrounding the attacks on handwriting evidence in the courtroom.

The dispute on interpretation and presentation of handwriting evidence has been led by the work of Evett and other researchers. For instance, Evett has presented his work at many symposia [1] and workshops. Others such as Broeders [2] and Riess [3] have commented on issues arising from this work like the use of probability. They consider that it is possible to provide a more statistical basis by making certain assumptions.

The scientific basis of handwriting comparison is dealt with in a series of publications by Hecker. [4]

In contrast with those western studies, China has developed its own systematic examination method based on complexity and unique of Chinese characters as well as the principles of handwriting. Wang [5] has applied the systematic theory and classification which initially emerged in philosophy to the evaluation the value of handwriting characteristic. He deciphered that each characteristic of handwriting was an assignment in accordance with its stability and uniqueness. In the casework, the value of characteristic may be a valuable aid to the examiners.

Challenge of handwriting examination

Forensic document examination evidence has been admitted in courts of law for nearly more than 100 years.

Whereas handwriting examination is an interdisciplinary field that did not develop in an academic environment but rather out of judicial need.

However, the scientific basis of this field was quite often challenged by the lawyers and judge in recent years.

Much has been achieved over the past two decades in understanding and testing the reliability and validity of fault detection and exclusion (FDE). There has been a general acceptance worldwide by the forensic science community in ensuring the existence of scientific basis across all of the forensic science disciplines.

The feasible approach taken to validate the handwriting method needed to be target at the assessment and testing of FDEs themselves as the method itself could not be directly validated due to the cognitive processes by which handwriting examination tasks were carried out.

The forensic handwriting examiners accordingly were regarded as the instruments to be validated.

The existence of expertise in itself does not provide the judiciary with information regarding the potential the evidence has to be misleading.

In China, the debate of inconclusive opinion is always continued. Inconclusive opinions by FDEs provide some evidence of a conservative component of FDE expertise related to a greater understanding of the limitations of the comparison process. However, some lawyers, judge, and layman do not accept the inconclusive opinions. Those queries focus on the expertise which is based on the issues whose right or wrong is clear. Supposing the examiners cannot give an explicit opinion the skeptic probably challenge the expertise which it must be a bias as expected. For example, problems associated with disguised or simulated writings are likely due to the questioned handwritings displaying a combination of similar and dissimilar features. Therefore, the rates of inconclusive opinion expressed in these types of caseworks are higher than that of others.

  Forensic Document Examination and Mathematical Methods Top

Mathematics and mathematical methods

There are obvious advantages to describing objective matters and rules through mathematics. Mathematics can ensure preciseness in quantities, notations, and generalization and also ensure that the computer techniques applied are feasible. At present, qualitative analysis is commonly used in forensic document examination, which means that final evaluations are based on an expert's own specialized knowledge and empirical research. However, forensic document examination has always been criticized for the limitations of empirical evidence. Moreover, consideration should be given to the fact that quantification theories are becoming more and more significant in the field of forensic document examination.

Mathematical methods in forensic document examination

It has been near 20 years since mathematical methods were first applied to the field of forensic document examination. In recent years, the application of mathematics has led to great progress and preliminary achievements.

Probabilistic method

The probability theory in mathematics mainly researches regularity within a large number of random events. A random event implies that even under the same circumstances, the results engendered by the same event are not the same, or at least not completely. In forensic document examination, similar problems are often identified, the characteristics of which sometimes cannot be precisely predicted, because the presence or absence of features involves high randomness. For instance, with regard to features that appear in printed matter during the printing process, some may be formed during the plate-making process, some during the printing process, while some may be caused by other reasons, thereby resulting in the outcomes of the characteristics of a variety of reasons; exactly what kind of result may appear cannot be determined in advance. Thus, we can consider the features that appear on the object of these tests as a random event. The minimum number of such features that should be selected when carrying out a unified inspection can be calculated through probability estimation.

Linear regression analysis method

Regression analysis is a mathematical statistics method for processing a mathematical correlation between variables. Usually, the relationships between variables are of two types: One is a function, and the other is a correlation. There are many problems to be studied in forensic document examination, such as the relationship between age and the frequency of words; the relationship between education level and writing level; the relationship between the displacement of printed dots and page; the relationship shared between all the variables above is correlation. For the purpose of establishing a general rule for these uncertain relationships, linear regression appears to be an available method [Chart 1].

Fuzzy mathematical analysis

Fuzzy mathematics is a new branch of mathematics, and it is from the number of vague concept study to determine the nature of the quantitative analysis so that the vague concept clarity. Fuzzy mathematics is applied to comprehensively evaluate a few vague concepts. This method provides the appropriate tools for forensic document examination to solve specific, vague phenomenon. Xie and Fang, [6] discussed the possibility and necessity of fuzzy application to handwriting examination as well as introducing the degree of membership which was applied in handwriting and speech recognition. Wu and Li [7] explored it was feasible that the fuzzy can be applied to age dating of writer and dating of stamp impression.

Because there are a lot of fuzzy concepts in forensic document examination, we could learn to use fuzzy math methods. For example, when describing a questioned handwriting feature "writing level," we usually use "high level of writing," "low level of writing," or "moderate level of writing" and other terminology are fuzzy concept such as "high," "low," "medium," which are based on expert judgment, that is, merely subjective criteria (including the identification of human visual experience, judgment, and personal experience, etc.,) obtained, other handwriting features are also similar: "High" and "low," "more" and "less," "strong," and "poor" and there are no clear boundaries of fuzzy concept. Obviously, handwriting features expression only in phase of the vague concept often makes it ambiguous and confusing, if fuzzy mathematical methods in the "eligibility list," etc., with a more precise quantitative relationship to express vague concept, will enable the handwriting to be much more clear.

In addition, the model approach, mathematical logic, could also be widely applied to the study of forensic document examination in the future.

An important feature in the development of modern science is the increasingly extensive application of mathematical methods, which should be reflected in forensic document examination as an interdisciplinary science itself.

However, there is still a long way to go. The biggest problem is not the quantitative analysis itself, but rather that few people who are forensic examiners understand mathematical statistics, as well as few mathematical and statistical researchers, are good at forensic document examination. In addition, the quantitative analysis of a document requires specialized knowledge in both fields. Moreover, computer knowledge and skills are indispensable for modeling and computerization implemented in forensic document examination.

In a worldwide perspective, a number of researchers conduct a series study on how to promote the foundation of forensic document examination, for instance, Bayesian theory based on logical framework applied to forensic science and Fourier method applied to letters of writing, which aim to develop diagrammatic analysis of handwriting. Taking the complexity of Chinese writing into consideration, we should explore an appropriate way to construct an analysis system closely connected with Chinese character.

If mathematical methods are applied to describe and illustrate an original that is examined and its variation as well as the relationship between the original and its features, it will undoubtedly make forensic document examination more reasonable and logical.

  Physical and Chemical Methods in Forensic Document Examination Top

Initially, the equipment used in forensic document examination was paper, pen, and magnifying glass in China; however, this equipment is no longer used nowadays. In recent years, along with the development of physical and chemical analysis as well as instrumental analysis, techniques of forensic document examination have significantly improved, which has played a vital role in solving crimes and obtaining evidence.

In general, there are a number of questioned documents that require physical and chemical analysis for objects such as paper, ink, stamp inks, and glue. By analyzing the components and structure of these objects, we can recognize and compare them to carry out an examination; we can also determine the relative date of the document.

The following are some physical and chemical analysis methods that are applied in forensic document examination:

Optical inspection

Morphology identification of questioned documents can be performed using various optical microscopes. Further, we can also distinguish one type of ink from another based on reflected light, refraction, polarization, and other characteristics of light.

Spectral test

Ultraviolet (UV) visible reflectance spectra of the microscopic photograph. The photographic method can be used to identify similar colors of ink, which is much more reliable than optical microscopy or visual observation. Fluorescence microscopy can be used to detect the ink of the paper and some paper additives (light-emitting fiber and plastic material) that have emission spectra. UV spectrometer measurements could be combined with other instruments to detect questioned documents.

Raman spectroscopy has been widely used in the forensic investigation of questioned documents involving stamp inks and writing inks. In addition, Raman scattering was used to determine a sequence of heterogeneous intersection strokes such as those from ballpoint pen ink (red and black), pencil, and laser printer toner except stamp ink and ballpoint ink or gel pen ink (all colors).

Chromatographic test

It is widely used in forensic document examination especially for detection of the type of writing materials and ink dating.

Thin layer chromatography

Thin layer chromatography (TLC) can complete the separation of the high efficiency of the mixture during a short time and with high quality. Besides, by use of the instrument, the examination would be easy to operate, and with the advantage of easy separation, high sensitivity, high efficiency.

TLC has been used to identify ink components, laser printer toner, inkjet ink, and paper.

High-performance liquid chromatography

This technique has high speed, high efficiency, high sensitivity, and operational automation features. High-performance liquid chromatography has been successfully used to identify ballpoint ink and gel pen ink ingredients.

Gas chromatography (gas chromatography/mass spectrometry)

Gas chromatography in document examination is often used to identify the nature of the ink, as well as to determine the origin of the ink composition and ink identification.

In general, the suspect material (such as ink, handwriting, signature, paper, and seal impression) of forensic document examination is usually a piece of evidence or closely related to the fact-finding in a specific civil case or penal case. Take many factors into consideration, the questioned or examined document should be performed the nondestructive test in any way except ink dating analysis or ink identification. Accordingly, a variety of physical methods can be well-applied to this field rather than chemical methods as well as those methods that may damage the examined material.

  Forensic Document Examination and Computer Technology Top

Following the popularity of computers, the application of computer technology to the field of forensic document examination arise the attention of examiners. At present, there are two types of computer assistant software: One is a computer aided system, which makes feature comparison tables and facilitates configuration comparison, creates examination reports, case file management, etc., the other is real automatic identification, such as seal automatic matching system (SAMS) and handwriting automatic recognition system (HARY). The former one offers good support in regulating examination procedures and improves identification quality; for the latter, the theoretical and practical issues are yet to be explored in depth.

Computer assisted handwriting examination

The domain of computer-assisted handwriting examination is a hot topic both at home and abroad. Kroon [8] has suggested the use of SCRIPT as a training tool.

Mohammed [9] has considered the Write-On software program as a new aid to handwriting comparison. He found it valuable aid for large cases involving a number of documents. He suggested it was useful in developing statistical data to support analysis. It can also be used as a sophisticated way of making comparison charts for the courtroom. Liu et al. [10] reports on a multi-layer dynamic system for the verification of Chinese signatures. This uses a combination of five different kinds of features to reduce the time and increase verification. In a recent couple of years, a few Chinese researchers have made efforts in this specific field. Xiaowei [11] carried out a pilot study on computer handwriting identification and illustrated the feasible procedure as well as the limitations of computer-assisted handwriting examination. Ping et al. [12] separated the computer-assisted handwriting examination from the computer assistant identification while the former is assisted software and the latter is a technique of automatic identification of handwriting.

Because of the complexity and diversity of Chinese characters in terms of font and structure, coupled with the fact that a suspect may deliberately disguise his/her writing, it is extremely difficult to make use of computer-assisted handwriting identification systems. To develop a set of characters suitable for computer intelligent HARYs, we need to pay more attention to the following three aspects:

  1. The automatic selection of writing features: From handwriting samples or samples of handwriting, the characteristic value of the word is automatically selected
  2. The automatic extraction of handwriting characteristics that is, from the selection of the feature words, valuable features can be extracted
  3. Connected with background information of the case, the evaluation of handwriting characteristics can be assessed from samples.
Computer assistant identification

Discussion meeting online

It is necessary to organize special discussions that consist of several experts to solve particularly challenging issues. In recent years, computer network information technology has greatly improved, breaking territorial limitations, which may have been a problem in the past. Today, it is possible to hold discussion meetings online with the help of modern network technology to help promote and discuss the field of forensic document examination.

Image processing assisted system

Photoshop can not only manipulate original images through processes such as image dyeing, colored processing, image cutting, and splicing, but also enhance the image sharpness for altered documents, illegible handwriting, and breezing stamped impression. The comparison between questioned documents and reference documents can be clearly and accurately displayed through Photoshop image processing methods. It is easy for examiners to draw a conclusion by means of the outcomes outputted by the image processing system. Photoshop systems can be used for handwriting and seal verification through techniques that transform the light, color, shape, or resolution to improve the clarity of observation.

Digital signatures

Electronic signature capture pads record our signatures at shopping malls and even for insurance policy documents. Forensic document examiners have examined printed versions of signatures generated from electronic signature capture pads, and now actual digital files may be submitted for examination. Forensic document examination is stepping forward into a new era: The examination of digital signature files is a case in point for the future.

  Standards or Criterion of Forensic Document Examination in China Top

At present, the forensic document examination laboratory mostly refers to publications that were established by China National Accreditation Service for Conformity Assessment. For instance, the accreditation criteria for the competence inspection bodies (Identical to ISO/IEC17020:1998) and a series of application guidance and explanations that were developed against specific criteria in specific technical areas for basic fundamental criteria are in use. However, there is still a gap in application instructions or guidelines that are associated with Forensic document examination. From the standards of FDE's point of view, nine standards in a total of FDE published by the Ministry of Justice PRC are recommended to domestic FDE's laboratory. While in the Police Department, there are currently 17 standards or criteria being employed for internal use only which are not yet opened to the public. Compared to the standards established by the Ministry of Justice PRC, the structure and the style of both standards focus on basic consistency, while the standard classification of internal homemade standards of the criteria of the Police Department are more refined. Take handwriting identification, for example, it is classified into normal handwriting identification, disguised or forged handwriting identification influenced by conditions.

  Challenges to Forensic Document Examination Top

The majority of practitioners of FDE are concerned with the technique of this field rather than the value and the limitations of the findings. For instance, what does the result of handwriting identification mean? If the expert report says: "…Match…," or "…similar to…," or "…the same as…," can it be explained what the implications of the result are?

However, little has been done to meet the challenge of assuring that the reports include both value and limitations. In other words, they are to some extent interpretable to a large number of users such as the police, clients, lawyers, and juries. In addition, forensic document examination as an empirical discipline will not go further without establishing a common cognition. It will not progress and will not be able to assist in judicial processes unless a common understanding of what the findings imply are established.

Besides the report writing, the validity and reliability of forensic document examination is also generally disputed all over the world. How to minimize human bias and maintain ethics supposing you are a qualified practitioner? How to well apply the statistics and uncertainty of empirical experiments like handwriting identification? The forensic document evidence still requires professionals to devote themselves to solve such challenging issues.

In view of the media reports, the latest released revelations of systemic defects and forensic examiner errors existing in the USA crime laboratories especially in DNA immunity cases, and other examples of wrongful convictions, the current mode for training or educating as well as the procedure of examination arouses some lawyers' criticism. It is good lessons for us who are engaging in forensic document examination both rigorous examination in each case and highlight in training and educating.

  Conclusion Top

Researchers will continue to examine the frequency of occurrence of handwriting characteristics with large population studies to assess the value of certain features.

More forensic document examiners will introduce statistical methods to further enhance the foundation of the science supporting forensic document examination.

Image capture devices will provide better, higher resolution electronic images of everyday business documents evaluated by forensic document examiners.

Computer software and automated systems such as HARY and SAMS will continue to develop and expand into general use, further assisting examiners in their work.

The research will continue with more funding for forensic document examination projects. The comparative methodology of forensic document examination will continue to be strengthened by basic research and new technologies to assist researchers in improving the science.

Last but not the least, we have to pay more attention to enhance the explanations of the findings of forensic document examination, improve the training and education as well as decision-making of forensic document practitioners regarding which absolute uniqueness is not sufficient to portray a possibility in case the association between evidence and source is not that explicit.

Financial support and sponsorship

Collaborative Innovation Center of Judicial Civilization, China.

Conflicts of interest

There are no conflicts of interest.

  References Top

UK, Forensic Science Service, EVETT: Forensic Handwriting Comparison, Probability and the Nature of the Science, ***given at 10 th ECPGHE (Joint Meeting of the European Conferences for Police and Government Handwriting and Documents Experts), Tulliallan, Scotland; 1998.  Back to cited text no. 1
Broeders AP. Some Observations on the Use of Probability Scales in Forensic Identification. Vol. 6. Rijswijk, The Netherlands: Netherlands Forensic Institute, Forensic-Ling; 1999. p. 228-41.  Back to cited text no. 2
Norbert Köller, Kai Nissen, Michael Riess, Erwin Sadorf, Probability Conclusions in Handwriting Opinion: The Standardization of the Language in the area of degrees of Probability. Press of Luchterhand (BKA); 2001  Back to cited text no. 3
M.R. Hecker, Treatise on the Scientific Foundation of Forensic Handwriting Comparison, published by Kolonia Ltd; 2000.  Back to cited text no. 4
Wang XC. Systematic Classification and Examination of Characteristics of Document Evidence. China: Press of People's Public Security University of China; 2011.  Back to cited text no. 5
Xie P, Fang J. Fuzzy theory and application in document examination. Journal of China Criminal Police University 1994;4:8-10.  Back to cited text no. 6
Wu DH, Li B. Application of Fuzzy Mathematical Method in Document, impression Examination and Recent Development. The 4 th Theory and Practice Academic Conference of Forensic Document Examination of China. Press of People's Public Security University of China; 2003.  Back to cited text no. 7
Netherlands, Nifo, Leny Kroon: Script as a training tool; 1998. Given at 10 th ECPGHE Tulliallan, Scotland; 1998.  Back to cited text no. 8
Mohammed LA. Write-On: A New Tool for Handwriting Comparison, Associated Document Examiners. Vol. 2. San Diego, CA, USA: J-AM-SOC-QUEST-DOC-EXAM; 1999. p. 104-8.  Back to cited text no. 9
Liu K, Cheng KC, Wen CJ, Yau HF, Jeng BS. A Chinese Signature Verification System Using the Multi-Layer Decision Method. Vol. 5. Taipei, Taiwan, China: Scientific and Technical Research Centre; MJIB, INT-J-FORENSIC-DOC-EXAM; 1999. p. 97-101.  Back to cited text no. 10
Xiaowei AI. Pilot Study on Computer Handwriting Identification. Journal of Hebei Vocational College of Public Security Police 2005;5:22-26.  Back to cited text no. 11
Ping LI. Computer-assisted Handwriting Auto-identification. The 7 th Academic Conference of Forensic Document Examination of China. Press of People's Public Security University of China; 2008.  Back to cited text no. 12

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