Special types and methods of forensic investigations in case of mechanical damages

  • Damage on the body
  • Multiple injuries
  • Physical-technical research methods
  • In the analysis of the damage and of the various traces of external influence is important determination of the nature of their origin, that is connected with the identification of damaging guns.
    The objects on which remain prints of other items in criminology is designated as sadovospasskaya, and those objects which they appear, as Kadoorie.
    Branch of forensic science that studies the tracks as the display of the external structure of objects for the purposes of their identification or establishment of their group membership, called trasology.
    Features of external structure of damaging items at mechanical influence appear as various kinds of tracks: traces of prints (for example, a depressed fracture of the skull with a hammer blow, an imprint of the tread of the tyre footprint Boiko drummer on the cap sleeves and others) and traces of tracks (with a cut bones axe, drawing and others).
    Damage service from the effects of traumatic items can be quite varied, depending on the nature of the subject and mechanisms of external influence. The identification shall be part of the damaging objects, the impacts of which in varying degrees, found displayed on your clothing or body.
    Blunt objects with ample surface of a direct blow on clothing and body form a trail - square-defined borders of the contact. The clothes and the body can stay overlay (for example, contamination of the soil in the fall). The impact of a blunt object, with clearly defined edge or boundary, leaves on clothing seal fiber in accordance with their path, and at a sufficiently sharp edge - even disconnected apparel fabrics.
    Hitting a subject that has on its surface pollution (soil, technical grease), leaves on clothes accurate contour. Accordingly, the contour of the body, the formation of bruises or wounds (blows wrench and others). When exposed to very significant force may razmytye apparel fabrics (for example, moving the wheel of rail transport). In the process of shock interaction on traumatic gun remain fiber particles damaged tissue service (overlay). In traumatisation of the body in places not covered by clothing, damaging the instrument can be detected as overlapping scales of epidermis, hair, blood.
    Signs of blunt solid objects in a number of cases identified quite easily (for example, an imprint of tread wheels), in other cases, the establishment of their difficult and requires special laboratory tests (for example, detection of metallization at the point of impact).


    Fig. 74. Traces of slip-on shoes.

    Tangential impact blunt objects often calls, in addition to the contamination of clothing (e.g. drawing), its damage in the form of gaps. When hitting a part of the vehicle pedestrian last before the fall often gets rotational motion around the longitudinal axis of the body. In such cases, with outer soles of shoes arise characteristic traces from the slide (Fig. 74).
    When moving through the body of the car can occur traces overlays from the tread of the wheel and traces of damage. It should be stated that both those, and others often do not reflect fully the path of damaging subject (wheels) and at best give a sense of tyre model (but not the car).
    Quite typical is damage to service in the form of a kind of smoothing wrinkles, tears in parallel the seams, the default buttons in tension service as a result of rolling wheels (Fig. 75).


    Fig. 75. "Smoothing" folds of clothing wheel of the car when moving (the arrow for the direction of movement of the wheel).

    Fig. 76. Imprint tread wear and its gap due to the impact

    Gaps service from tension usually are cross orientation relative to the direction of external influence (Fig. 76).
    Breaks always have a linear or rectangular in nature, coincide with the direction of the warp or the weft. The mechanism of their formation is to stretch threads tissues, followed by a gap, and therefore broken threads are spindle spongy ends.
    Under the action of cutting subject threads on the edges of the defect smooth, and the incision, as a rule, does not coincide with longitudinal or transverse direction of fibres, and in varying degrees, cross them at some angle. Cut damage service may have not linear form, and zigzag in cases where the blade damaging weapons cuts through several layers of clothing, gathered in folds. Mild cutting tool, in addition to the incision can cause breaks.
    When exposed to cutting damage service often continue in the form of impressions from the blade, which entered into contact with clothing. If a strong blow with an axe and a deep dive blade ends of damage on the clothes take the U-shaped form, especially in cases of preferential immersion "heel" or "toe" of the blade of the axe.
    Damage service caused piercing and cutting items, depend on the shape of the blade and its cross section. The object of the blade and butt, forms the damage, resembling an exclamation mark, while dvuletnee weapons (two-edged) causes damage, reminiscent of the cut. Stab damage on clothing in length can far surpass the wound in cases when removing damaging of the object of wounds changes the angle and there is an additional section or by the action of the tip of the blade, or the edges of the back.
    Puncture damage service arise from expanding apparel fabrics and tear separate threads or prirastajte. Such a mechanism of damage contributes to the fact that on the edge of damage due to friction is formed band wiping, laboratory researches which allows to determine the nature of the metal damaging guns, and in some cases to differentiate piercing and fire-arms. In addition, important information can give studies foreground (grease, impurities from the area of the belt down.
    It is established that astronomicheskie round section items when submerged speed of up to 3 m/s form folded radial relief around the hole with the deposition of metal damaging the guns on the top of the folds of the clothing. Dive with greater speed usually did not work (Fig. 77).


    Fig. 77. Puncture damage service. The nature of the deposits of the metal around damage to clothing. and - with a sink rate of 3 m/s; b - 0,5 m/s; in the acute - angled.

    At gunshot injuries on clothes settles most of the components, related to the shot, while on the body they may be completely absent. It should be borne in mind that on fabrics of different color and quality of these components are identified differently and, in addition to external inspection of the area of damage, you must use laboratory methods of research.
    Damage to the clothing shall be subject to a thorough examination and description of the measure the thickness of the layers of clothing, which together with the determination of the depth of the wound channel allows to judge about the length of the wound of the sword.
    In the process of production of the external examination of a corpse in his study in the morgue is a very important component is the use of direct microscopy. Using an operating microscope (stereoscopic microscope MBS-1, fluorescent photodiagnosis and others) identify the properties of the damages to the clothing, especially pollution and overlays. Special importance should be given to using this method in the study of damage to the body.