(First published: January 1, 2024).
There are many different views on what constitutes evidence in the academic circles, such as the theory of facts, the theory of basis, the theory of materials, the theory of reflection, the theory of means, the theory of results, and the theory of the existence of law. Article 50 of the Criminal Procedure Law, as amended in 2012, defines evidence as "materials that can be used to prove the facts of a case", and adds that evidence must be verified before it can be used as the basis for a verdict.
materials that can be used to prove the facts of the case" is not many words and is very easy to understand, but the content contained in it is very rich. In other words, since there is no further definition of what constitutes "may" and "material", it can be applied to many different types of evidence, including electronic evidence and, of course, "audiovisual material" evidence as a subcategory of electronic evidence.
Taking the process of forming and extracting the audiovisual recordings that belong to the "audiovisual materials" as shown in Figure 1 as an example, the application of the relevant concepts involved in the definition of evidence to the evidence of "audiovisual materials" is illustrated.
, the formation process of video and audio recordings
The sound emitted by the perpetrator is an air vibration that travels at a speed of 340 meters per second, and when it travels to the pickup, the pickup converts the change in air vibration into the change law of voltage or current in the analog audio signal. The light reflected by the perpetrator is a generalized electromagnetic wave propagating at the speed of light of 300,000 kilometers per second, and when it propagates to the camera, the camera converts the change law of the incident light into the change law of the voltage or current of the simulated ** signal.
The analog audio signal output by the pickup and the analog signal output by the camera are all electronic signals in analog form, which are converted into digital video and audio streams and output to the TF card socket after being processed by the camera motherboard, so that the digital video and audio files can be stored in the TF card. TF card is a non-volatile electronic storage medium that does not lose data after power failure, which can be accessed at any time, and the entire camera can be extracted or only the TF card can be extracted as evidence in court during the inquest.
Evidence that can only exist in the field
The sound made by the perpetrator and the light reflected by the perpetrator are obviously strongly related to the criminal act and are primitive evidence;In addition, the sound and light completely disappear from the scene after being transmitted in the live environment, and the original object cannot be extracted as evidence in court, so it is a kind of evidence that can only exist in the scene.
Similarly, the analog ** signal output by the camera, the analog audio signal output by the pickup, and the digital video and audio stream output from the camera board to the TF card holder also have a strong correlation with the criminal behavior, which is also the original evidence;In addition, such signals completely disappear from the camera after propagating inside the camera, and its original cannot be extracted as evidence in court, so it is also evidence that can only exist in the scene.
Evidence that can be used as evidence in court
The TF card containing digital video and audio files is a non-volatile electronic storage medium that does not lose data after a power failure, which can be accessed and checked at any time, and its original can be extracted as evidence in court. If the model of the camera is special, and the digital AV files stored in the TF card cannot be used with a common (software) device, the original camera needs to be extracted on the spot as evidence in court. Compared with evidence that can only exist in the field, cameras and TF cards are tangible objects that can be seen and touched, and can be used as evidence in court at any time.
and evidence as the basis for the verdict
When digital AV files stored on a TF card are used as evidence in court, the following situations may occur:
1) The clarity is sufficient and the correlation between the recorded scene and the main facts of the case is very large, which is used as the basis for the verdict;
2) The clarity is too low or the recorded scene has little relevance to the main facts of the case, which cannot be used as the basis for the verdict, but it is still the evidence used in the litigation stage
3) During the trial, the court found that there were irregularities in the operation in the process of extracting the TF card during the inquest and inspection, which is flawed evidence, and is still the evidence used in the litigation stage
4) If the camera is found to be illegally installed and used during the trial, it is invalid evidence and still belongs to the evidence used in the litigation stage, but it cannot be used as the basis for the verdict;
5) In the supplementary investigation stage, image enhancement technology is used to improve the clarity so that it can meet the requirements of being used as evidence in court, and the correlation between the recorded scene and the main facts of the case is very large, and it can also be used as the basis for the verdict;Wait a minute.
In this case, although the voice of the perpetrator and the reflected light can only exist at the scene, they exist objectively, and their existence and changing circumstances can truly reflect the facts of the crime, and they belong to the original evidence that has a strong correlation with the criminal act, or whether they can only be found in the evidence that has not entered the litigation procedure. However, if it is considered that they are not evidence, then the evidence of "audiovisual materials" formed by the use of cameras to transform and record them is the result of the transformation and recording of non-evidence, which leads to the "audiovisual materials" evidence becoming illegal evidence, and such a derivative conclusion is obviously unreasonable. Therefore, in accordance with the principles of objectivity and impartiality, it should be considered that the voice of the perpetrator and the reflected light also belong to the category of evidence.
From another point of view, the light reflected by the perpetrator of the crime is an electronic signal, but the sound of the perpetrator speaking is actually a vibration of the air, but not an electronic signal, and they are all original evidence that can only exist in the scene, but they cannot be seen in the courtroom, but only the TF card. Therefore, it is popular to believe that only the TF card is evidence, and the light reflected by the perpetrator and the voice of the perpetrator are not evidenceHow to explain it?
Looking further, can't it be assumed that the light reflected by the perpetrator and the voice of the perpetrator are actually used as evidence in court in the form of digital video and audio files stored in the TF card?
Note: The main content of this article is taken from the first chapter of the "Introduction to Electronic Evidence" (textbook) in the author's trilogy of electronic evidence theory (Principles of Electromagnetic Wave Evidence, Research on the Recasting of Electronic Evidence Theory and Introduction to Electronic Evidence). Please respect the difficulty of original writing, and if you need to quote, please indicate the source!
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