The subject of forensic biological examination is factual data of identification, classification, diagnostic and situational nature, established using a complex of knowledge in the field of biology regarding objects of plant and animal origin and to the subject of evidence in criminal or civil cases.
Biological examination has two areas of expert research:
- research of objects of plant origin;
- research of objects of animal origin;
The objects of forensic botanical examination are particles of woody, shrubby and herbaceous plants (roots, rhizomes, leaves, stems, flowers, seeds, fruits, bark, wood, fibers), algae, sawdust, shavings, particles of wooden objects, hay, straw, moss, tobacco and tobacco products, plants containing narcotic substances, and other objects of plant origin.
The objects of forensic zoological examination are fragments of organs, tissues of mammals, birds, fish, its waste products, as well as insects. Objects of animal origin are derivatives of the epidermis of the skin of animals (hair), birds (feathers and underfur), fish (scales) tissue of animals, birds and fish (skin, bones, cartilage, etc.). There are also insects and its fragments; the waste products of animals, birds and fish are often elements of the material situation of a crime event, and are combined with other material traces of offenses. Animal hair, for example, when investigating crimes against the person, is found together with textile fibers of clothing; in a road traffic accident, along with hair, there are particles of paint and varnish coatings, glass, traces of fuels and lubricants, etc.
The objects of forensic biological examination are specific. They are characterized by relative stability, an exceptional variety of elements of the external and internal structure, including a complex of features, constant, stable, characteristic of certain taxonomic gradations and can be found on particles of very small sizes. In addition, these objects are characterized by the reproducibility of signs, the ability to maintain its structure even after separation from the whole organism. These features make it possible to solve classification problems.
The biological objects are capable of exhibiting the variability they present, depending on the living conditions that were in the process of the formation of this or that organism, its vital activity. Biological objects can react to the impact of various factors, including those associated with the event. All this makes it possible to obtain information for solving identification, diagnostic and situational (situational) tasks.
Nowadays, in expert practice, thanks to the available scientific developments, the tasks of belonging to a particular genus, species are being solved. Assignment to taxonomic groups below the species is difficult due to the small number of objects, changes in its original state.
The solution of classification problems for biological examination is to establish the nature of the object and the taxon, which, as a rule, reveal the properties of biological objects, expressed in external morphological, anatomical (histological and cytological) features. Moreover, from the number of its own features about objects, determination of belonging to a specific natural-biological group or to a group of narrower specification.
The classification task belongs to the main role in forensic biological examination.
The identification tasks of forensic biological examination are solved in the process of identifying an object by its materially fixed reflections, that is, the establishing a common taxonomic belonging based on the study of the classification (taxonomic) characteristics of the compared objects. Then the establishing the general group affiliation, individual-specific identity (belonging to common source of origin of objects; belonging of the object to a single mass, a single whole, a specific specimen of a plant, an animal, the fact of contact interaction).
The first step in solving identification problems is to establish a common taxonomic affiliation based on the study of the classification (taxonomic) characteristics of the compared objects.
At classification character research in the course of the decision of identification problems the comparative research of objects with each other (its quantity not less than two – the identifying object, and that which is identified) necessarily takes place. It is established, whether objects have general taxonomic affiliation, whether they belong to one group; the taxon and group are usually not specified. This is the main criterion for differentiating such research.
The next stage of identification is the establishment of a common group affiliation of objects. The assignment of compared objects into one group based on identification characteristics is an integral element of the tasks of establishing a single source of origin, belonging to a single mass, a single whole, as well as the tasks of individualization and identification of an individual (object). Taking into account the specifics of the objects under research (a limited set of identification characteristics), the determination of a common group affiliation can become the final stage of identification research, when the establishment of an individual-specific identity is impossible.
Situational tasks by its nature are close to diagnostic ones. Diagnostic tasks related to the analysis of the situation as a whole, when the object of research is a system of events, are called situational and are often considered as a separate group.
With regard to forensic biological examination, when solving situational tasks, studies are carried out related to the reproduction of the situation and circumstances of the crime event. In many cases, the solution of the situational task of forensic biological examination is associated with the establishment of the fact of contact interaction, which, as a rule, is of a complex nature (trace evidence, material science, soil examinations are carried out).
The most typical tasks of a diagnostic nature include as follows: establishing the type of action (chemical, mechanical, biological) on a biological object; the nature and method of separating its part from the whole, keeping it on the surface of another carrier object to establish the presence and causes of damage to a biological object.
The most common tasks of the diagnostic nature of forensic biological examination are the following: determination of the time of specific actions (events) for specific changes in biological objects in accordance with biological laws, the established states of the object, determination of cause-and-effect relationships.
It should be noted that in recent years, the range of research objects and questions related to the decision of experts have significantly expanded. Therefore, in expert practice, problems arise related to establishing the cause of the death of trees, the cause and degree of destruction of wooden structures, on the safety of life, material damage, etc. Thus, one of the most important causes of wood damage is the activity of xylophagous insects, that is, insects that feed and develop in the wood of arboreal and shrub species of plants.
Questions about the suitability of wood for use, its grade, the reasons for the destruction of the wooden structure, the time of infestation of wood by insect pests (before the start of wood exploitation or during operation) can also be resolved.
Nowadays, examinations are often appointed on the facts of falling trees, which entailed a threat to the life and health of people, resulting in material damage. At the same time, diagnostic tasks are solved (establishing the state of trees, the presence of its damage by insects, fungi, determining the degree of decomposition of wood). The subtasks (establishing the state of the soil, the presence of mechanical damage to a tree, its age, determining the stage of putrefactive processes, determining the nature of the influence of the presence of heating pipes laid before the fall of the tree, in the immediate vicinity of it, and in some areas of under the root system, etc.) which makes it possible to resolve the issue of the cause of the fall of the tree. To reconstruct the dynamics of an event according to the biological components of the material situation means to restore (reproduce) a certain system, limited by the time and spatial framework of a specific crime (incident), as well as material (biological, etc.) elements of the environment that affect the mechanism and method of committing an offense.
In addition, in expert practice, there are problems associated with establishing the cause of oppression of plants in crops, changes in grain quality indicators during storage, damage to planting material, vegetable crops during transportation, etc. Therefore, in the course of expert research within the framework of the implementation of resolutions, determinations, specialists from other institutions of the relevant directions are involved to conduct comprehensive examinations related to lawsuits:
- due to the careless management of farmers, unprofessional tillage, which causes crop failure;
- application of excessive doses of chemical fertilizers and plant protection products, causes an environmental threat;
- non-compliance of seeds with the requirements of current state standards causes a decrease in the quantity and quality of the desired crop.
Therefore, with regard to forensic biological examination, situational tasks should be of an integration nature and consist in establishing the mechanism of interaction of the objects of the event under investigation, thereby ensuring the reproduction of the tested (investigated) events.
The list of questions of forensic botanical examination
- What is the nature of this object? If it is of biological origin, then what is its taxonomic affiliation?
- Are there micro-objects (particles) of biological origin on the carrier object (it is indicated in which one)? If so, what is its taxonomic affiliation?
- Do the given mass (for example, grain in a bag taken from a person) and samples taken in a specific place (for example, grain samples from a certain storage) have a common genus (group) affiliation?
- Do the samples of cereals (legumes) submitted for research meet the requirements of DSTU (State standards of Ukraine) in terms of: mass fraction of protein; mass fraction of crude gluten; gluten quality; the number of falls; humidity; garbage and grain impurities; smut grain; weight of 1000 seeds (grains) (nature)?
- Do the samples of cereals (leguminous) crops submitted for research, according to its characteristics, correspond to the terms of the supply contract?
- Are these objects parts of one whole (for example, a branch and a trunk, two parts of a plant leaf, etc.)?
- Could certain changes occur in the development of a plant object within a certain period of time (or could the plant grow after a while with the existing size, etc.)?
- What is the age of the plant, its parts?
- Does this plant (crushed plant particles) belong to those that contain narcotic substances? If so, what is its taxonomic affiliation?
- Have the given samples of narcotic drugs been compiled in one mass?
- Do these samples of narcotic drugs have a common generic (group) affiliation (by the method of manufacture, place of cultivation, etc.)?
- To which variety (hybrid) does the seed submitted for research belong?
- The list of questions of forensic zoological examination
- Are objects detected and removed by animal hair?;
- Is there animal hair on the presumed objects-carriers? What is the genus of hair?;
- What is the method (mechanism) of separation of the tested hair from the carrier, its sources?;
- Are there any destructive changes on the hair?;
- If they are, then as a result of what actions were formed; the origin of this hair;
- Does the identified hair have a common genus?;
- Were there any objects-carriers on the surface of which hair was found, a common generic and group affiliation, in contact with each other or with a specific fur product, or with the hair of a certain animal?
Features of examination appointment
The biological objects that carry information about an event can be in a vital state and obey certain biological laws (developmental cycles, rhythms, etc.), which cause irreversible changes in it. As a result, there is a complete disappearance of information (change of signs) or the destruction of the objects themselves (with rotting, fermentation, mold or bacteria damage). Therefore, it is necessary to deliver biological objects to an expert institution as soon as possible.
When removing biological objects, the following should be avoided:
- excessive moisture (dry it at room temperature until the disappearance of water from the surface of the object);
- sealing (that is, it is unacceptable to pack living biological objects without air access);
- exposure to elevated temperatures (proteins that make up biological objects denature at a temperature of about 60 °C).
If it is impossible to deliver a biological object to an expert institution in the shortest possible time, it must be preserved, that is, fixed in the state in which it was found: cooled or frozen, dried, placed in a preserving liquid.
At the site of the accident site, it is necessary to select representatives of all plants and animals (or a fraction of its covers), especially those that could have been exposed to certain objects.
Separate packaging is necessary for both representatives of the botanical and (especially!) zoological world (larvae, egg laying, insects, and mollusks).
It is unacceptable to separate complexes of biological objects that carry common information, for example, one trace. At the same time, it is necessary to take measures to preserve such a complex, packing, for example, the plant and the insects on it separately.
Agronomists, process engineers, establish the quality of grain products. The expert biologist establishes the group affiliation.
If it is necessary to study compound feed and flour, the average sample is 0.5 kg.
Documents about its composition are attached.
Samples of tobacco and rustic tobacco should be seized either in full packages (packs), in bulk (some types of cigarettes) or in the form of raw materials weighing at least 5 g. All material is removed from the scene. Packing tobacco and rustic tobacco in paper bags.