Using special knowledge in evaluating a copy of a trace as derivative evidence

The paper highlights the problems of evaluating copies of material traces from the point of view of the possible loss (partially or completely) of their evidential value. The analysis of the reasons for the distortion of the copy in relation to the original shows that it is not possible to provide for all of them, but the main ones should be identified: non-compliance with technical and forensic recommendations for fixing and copying the material trace; bad weather conditions that directly affect the process of making a copy; intentional or careless actions of the person performing the copying, or his assistants, etc. A proposal is made to improve the organization of interaction between the investigator and the forensic specialist in the process of both obtaining a high-quality copy of the trace and assessing the possible partial or complete loss of its procedural value as derivative evidence. For the same purpose, it is proposed to provide copies of the trail for forensic examination, as well as photos (videos) of the materials of the initial forensic fixation of the original trail at the place of its discovery. The made recommendations should help to improve the efficiency of the expert's determination of the degree of change in the properties and characteristics of derivative evidence submitted for research, which is a copy of the material trace of the crime.