Material Evidence

Material Evidence, the most diverse everyday objects that can serve for detecting a crime and as evidence against a criminal. Among them, the most important are: instruments used to inflict injuries; clothing and underwear with traces of blood, semen, etc.; food that has aroused suspicion of poisoning; traces of feet and hands with their dactylographic prints, etc. Some material evidence must be taken for laboratory examination or presentation in court, for which it is often necessary, besides a representative of the criminal investigation department, for a forensic physician to be present, who can more correctly give instructions on the need for special examinations, e.g., chemical, microscopic, spectral, bacteriological, etc.; besides giving instructions, the physician must take all measures to preserve, properly collect, package, and deliver the material evidence for examination. Other material evidence, due to their bulk, due to easy spoilage, or inability to be separated from the place of discovery, must be described in detail, recorded with photographs and drawings; in any case, all measures must be taken to protect traces of the crime from spoilage and destruction. "Among the most frequently encountered material evidence of the latter kind are blood splashes, smears, stains, streams; then footprints of the criminal on the floor, soil, snow, prints of hands with dactylographic palm patterns. Blood splashes on the floor or walls can indicate the place of the initial attack, from which blood trails lead to the place where the body is found, and it is very important to establish whether the victim could have walked this distance himself or was brought here. Blood splashes have the shape of a sharp wedge, with a rounded blunt end, the length of which is greater, the more sharply the droplet falls. Its rounded end indicates the place of the beginning of the fall, and the thin end indicates its progressive movement. Usually splashes are formed from damage to large arteries, but it is possible with repeated blunt blows also from veins and tissues, and in the case of blows, blood splashes in the direction opposite to that of the striker, and the criminal may not have splashes on him. When blood droplets fall perpendicular to the surface, splashes take the shape of a circle or something close to it, with small protrusions along the periphery. Streams of blood on walls, clothing, and the body can indicate in what position the bleeding injury was inflicted, which sometimes makes it possible to distinguish suicide from murder by the streams of blood on the forearm of the hand that cut the throat. Finding bloody prints of hands and feet at the place where the body is found has great significance in exposing the criminal. But it must be remembered that bloody prints can be left by the victim himself, as well as by persons invited for examination, and often by outsiders before the investigative authorities arrive. In most cases, it is macroscopically sufficient to determine the blood origin of stains, especially at the scene of the crime; but stains suspicious of blood on the criminal or on objects belonging to him must be examined microspectroscopically. Of the preliminary tests for blood, the test with a 3% solution of hydrogen peroxide and the van Deen test with guaiac tincture are more commonly used. But as these tests, as well as many other colored ones, are not entirely conclusive. Microscopic examination of stains gives reliable results, provided the formed elements of blood have not been destroyed, but even in this case, finding in the stain particles of domestic parasites can indicate the origin of the stain from bites of bedbugs, fleas, and other insects. From preserved blood corpuscles, it is sometimes possible to determine the species of animal from which the blood stain originated. The expert often has to decide on the origin of blood (e.g., in rape, when the suspect explains the presence of blood on his underwear as intercourse with a menstruating woman). The presence of menstrual blood in a stain is generally determined far from easily: stains are often contaminated with urine; despite freshness, they have few well-preserved characteristic flat epithelial cells from the vagina and uterus, which occur singly or in groups, but far from in all cases; the macroscopic appearance of menstrual stains, however, is quite characteristic, namely - at the beginning and end of menstruation, the secretions have the character of serous fluid and are often very pale. Blood stains from damage to the hymen are small and few in number, of ordinary blood character; finding seminal fluid in them can be conclusive. For blood stains from hemoptysis and nosebleeds, the distinguishing feature can be a mass of mucus with epithelial cells of the respiratory tract, especially ciliated cells, and confirmation of this is the presence in them of particles soot, dust, etc., found in respiratory secretions in urban residents. The origin of stains from gastric or hemorrhoidal bleeding is recognized by the admixture of food or fecal particles in them. Blood from a ruptured boil contains a mass of pus cells, fat droplets, sometimes cholesterol crystals. Blood stains from crushed bedbugs, fleas, lice, flies deserve special attention, as these stains give a reaction to human blood, which can lead to undesirable conclusions if the excrement of insects in the form of egg-shaped or roundish grains, brownish-yellow or reddish in the center, or particles of the insect itself (if crushed) were not noticed under the microscope. Due to the multitude of factors affecting the coloring substance of blood, the age of a stain can be determined only approximately. Semen stains as material evidence have no less significance than blood stains in the process of exposing the criminal in cases of corruption and rape. Their appearance is well known. For conclusive proof of the seminal origin of a stain, the presence of spermatozoa is necessary, but the latter may be absent in undoubtedly seminal stains in diseases of the testicles, certain general diseases, alcoholism, etc. (see Azoospermia, Infertility); various methods of storing stains also destroy spermatozoa. Crystal tests for semen - Florence and Barberio reactions (see Barberio reaction) - are not specific; a negative result of them only gives the right to assume that the stain is not seminal. The danger of infection with venereal disease, provided for in Art. 150 of the Criminal Code, forces attention to be paid to gonorrheal stains, visually similar to seminal ones, but more often with yellowish or greenish tints. To distinguish gonorrhea from blennorrheic conditions, depending on inflammatory processes of non-gonococcal origin, it is necessary to detect the presence of gonococci, which Haberda found for several weeks in dried stains on linen and other objects. But since many authors found in the healthy and diseased urethra certain types of diplococci similar to gonococci, the mere microscopic confirmation of the latter is not yet sufficient for an exact forensic-medical conclusion; pure cultures of gonococci on a nutrient medium of human serum with agar are required. - In cases of infanticide, stains of meconium, brownish-yellow or brownish-green in color, play a significant role; they consist of "meconium bodies" - round or oval formations, clumps of granular decay, from various cells of the intestinal canal, amniotic fluid, downy hairs, and cholesterol crystals; the content of the components of meconium depends on the age of the child: if the stool is weakly colored, without cholesterol, down, and epidermal cells, then the fetus has not reached the fifth month; if there are cholesterol crystals but no down or epidermis, then the fetus has reached 5-8 months. The stool retains the properties of meconium for 3-4 days after birth. - At the scene of the crime, on the hands of the body, on the weapon, on the clothing of the suspect, etc., hairs (see) can be found, which as material evidence sometimes have great significance. - In criminal cases, the examination of fibers found during the investigation, like hairs, can give important indications. Besides animal fibers, plant fibers, natural and artificial silk, are also examined. The process of examining fabric fibers is very similar to the examination of hairs (see Fibers of plant t, i i s; i jr <i hf v 4!js =?1 k щ fe& tive). - Sometimes in head injuries, it is important to determine the presence of brain substance on instruments as material evidence. In rape, traces of bites from the criminal in the form of a plastic imprint of teeth on the skin can be found on the victim's body. A plaster cast of both jaws of the suspect, when compared with the imprint, can give weighty proof of the suspect's guilt (which is what happened, for example, in the Moscow Guberniya Court on July 1, 1927, when considering a case of rape and strangulation by hands). Besides the general fixation of any traces of crime, it is necessary to take care to preserve these objects for subsequent comparison when exposing the criminal."

For an accurate cast of a trace, the simplest method by Causse is suitable: drawing on a grid: the trace is covered with a fine rectangular grid, which can be made from thin threads stretched in a frame; on exactly the same grid on paper, even an inexperienced person in drawing can make an accurate outline of the trace (see figure). If a footprint is impressed in mud, dust, or snow, then to obtain copies from it, sieving through a sieve of fine powder of plaster or cement, mixed equally with sand, is applied to the trace, pre-dried with blotting paper; cloth is placed on the powder, which is carefully watered from a watering can; when the hardened cast is removed, a mold is obtained, completely similar to the original trace. If the trace is imprinted in a stable mass (clay), then a plaster or cement paste-like mixture is poured onto it, or after pre-heating the trace, it is filled with powder of stearic acid. With the application of dactyloscopy methods in criminal investigation, material evidence, in the form of simple prints of the tips of fingers, have acquired great importance in searching for criminal elements in cases of major thefts and break-ins: dactyloscopic prints of criminals on various objects to which the criminal's dirty hands have touched repeatedly made it possible to prove the guilt of the suspect (see Dactyloscopy).

A-footprint; B-application of grid to footprint; C-grid on paper; D-transferred to grid drawing corresponding to the contour of the footprint (according to Bokarius). 1928; Minakov P., On hair from a forensic medical point of view, Moscow, 1894; von H o I-m a n n E., Lehrbuch der gerichtlichen Medizin Berlin-Wien, 1927.

A. Kryukov.