The tasks of forensics

Among the main tasks resolved by forensic examinations by the nature of the main objectives of the expert study, it is possible to identify identification tasks aimed at identifying an object by its mappings (in a particular case, traces). When solving identification tasks in objects identified (identified) and identifying (with which identification is made), common (group) and particular features are identified, they are compared and based on the coincidence of the totality of particular features, an individual-specific identity is established.

If for individualization of private signs it is not enough, then the solution of the identification task is completed by establishing the group identity of the object, i.e. by establishing the belonging of an object to a certain set (group) of homogeneous objects, carried out on the basis of studying the common features peculiar to all objects of this group. The definition of group membership is the initial stage of any identification research. Having determined the coincidence of common signs, go to the private. However, individual identification is not always possible. If there is not a sufficient set of private signs, it is necessary to limit the establishment of group membership (for example, state that the document is printed on one of three laser printers, which are selected from the 20 studied). The greater the number of traits studied, the smaller the number of homogeneous objects that make up the group.

A form of establishing group membership is the definition of a single source of origin of objects. For example, bottled wine and wine remaining in a cistern belong to the same batch. Signs can determine the composition and structure of a substance or material, reflect the production technology or storage conditions of objects, etc.

Another group of tasks - diagnostic - is to identify the mechanism of the event; time, method and sequence of actions, events, phenomena, causal connections between them; nature, qualitative and quantitative characteristics of objects, their properties and characteristics that are not amenable to direct perception, etc. For example: what is the mechanism for the occurrence of a fire or a traffic accident; What are the composition and manufacturing technology of this food product, how does it differ from the product manufactured in accordance with the approved technical conditions, etc.

A special case of diagnostic problems are classification problems. These tasks are aimed at establishing the compliance of an object with certain, predetermined characteristics and attributing it on this basis to a certain class, genus, species. An example is the forensic metalworking examination, when it is necessary to establish which brand this alloy belongs to.

Since the solution of classification problems in many cases precedes identification, some authors single them out into a separate group. However, we believe that by their gnoseological essence these classification tasks are diagnostic. Do not confuse diagnostic classification problems and identification tasks, the solution of which establishes the group identity of the object. Certainly, classification is also an assignment of an object to a certain group (genus, species), but this group is not defined quantitatively and the solution of this diagnostic task does not imply individual identification. For example, a piece of wood on a car’s bumper is part of a Korean pine trunk.

When establishing a group affiliation, the essence of the identification task consists in narrowing, as far as the identified identification features allow, the groups of objects containing the desired one, and this group, no matter how large, is always finite.

Diagnostic expert tasks according to the degree of complexity are divided into simple and complex. Simple diagnostic tasks include the following:

1) diagnosing the properties and state of the object, namely:

- study of the properties of the object, its compliance with certain (specified, established by the standard) characteristics;

- determination of the actual state of the object, the presence or absence of any deviations from its normal state;

- establishing the initial state of the object;

- determination of the causes and conditions for changes in the properties (state) of the object;

2) diagnostic studies of the properties and state of the object by its display:

- determining the degree of informativeness of the trace;

- the establishment of the properties and state of the object at the time of occurrence of the display;

- determination of the reason for changing the properties or state of the object. Complex (composite) diagnostic tasks are the study of mechanisms, events, processes and actions by results (objects, mappings). These include:

- determination of the mechanism of the event, process, action;

- determining the possibility of judging the mechanism and circumstances of an event by its results (consequences, mappings) of individual stages (stages, fragments) of an event;

- the establishment of the mechanism of the event in its dynamics; establishing the possibility (impossibility) of performing certain actions under certain conditions; determination of compliance (non-compliance) of actions with special rules;

- determination of conditions (conditions), time (period) or chronological sequence of actions (events);

- determining the place of action (its localization, boundaries), the position of the participants; determination of other conditions;

- definition of cause-effect relationships between actions and consequences.

Another reason is the division of diagnostic tasks into direct and inverse. Direct diagnostic tasks - moving from cause to effect. As a rule, these are simple diagnostic tasks of the type, what is the composition of this object or its structure, what temperature does the spontaneous combustion of this substance occur, and others. research.

Most of the complex expert tasks resolved by forensic diagnostics are reversed - from effect to cause. The main method used in this case is mental, physical, and mathematical modeling. Compare: the direct task is to establish the composition and the grade of the metal from which the vehicle part is made, and the reverse task is to reconstruct the “biography” of this part, to establish the technology of its manufacture or the reasons for the fracture, etc.

Diagnostic tasks associated with the analysis of the situation as a whole, when the system of events is the object of study, is called situational (situational) and is also sometimes considered as a separate group. Usually, this term is understood as complex inverse diagnostic problems. An example of solving a situational diagnostic problem can be the establishment of a mechanism of a road accident during the production of a comprehensive forensic road traffic and transport trasological examinations.

Along with the above classification, expert tasks are also classified for other reasons. So, according to the degree of generality, the tasks are divided 1 into: general - tasks of the kind of examination, typical - tasks of the type of examination and specific tasks of this expert study. The general tasks of the examination determine the goals in the most generalized form and give an idea of ​​the subject matter of this kind of expertise. Typical tasks of the type of examination, which are given in the reference literature, are formulated for each object of this type and serve as orientation for the formulation of specific tasks. Specific tasks are tasks assigned to an expert in the production of a specific examination.

Expert tasks are inextricably linked with issues submitted for the resolution of forensic examination. General and typical tasks are a scientific generalization of all kinds of questions on a given genus or type of expertise. The specific tasks of the forensic examination are implemented by posing specific questions to the expert, depending on the available objects and materials of the civil case.