Identification of “Fort” pistols and shot distange using stepwise discriminant analisis: an experimental study on human body simulators with consideration of clothing

Abstract

The increase in the use of fi rearms is a new challenge for various authorities, including the forensic medical service. The creation of new samples of fi rearms and cartridges for them requires constant updating of the theoretical knowledge of forensic medical experts for the most accurate answer to such key questions as identifi cation of the weapon and the distance of the shot from it. All this requires preliminary ballistic experiments. Considering the ethical and scientifi c components, it is most appropriate to use a non-biological imitator of the human body. Aim of the work. Creation of reliable discriminant models for identifi cation of «Fort 9R» or «Fort 17R» non-lethal pistols and their fi ring ranges. Materials and methods. An experimental study was carried out on bare and gelatin blocks covered with various types of textile material, followed by a study of damage to the covering material, the blocks themselves, and laboratory analysis using the chromato-mass spectrometric method, infrared microscopy, and X-ray fl uorescence spectroscopy. Results. For the identifi cation of the investigated pistols, the discriminant variables are the relative concentration of zinc, the specifi c sum of the length of cracks in the body simulator at a depth of 1 cm, the number of clothing tears and the distance of the shot; to identify the distance of the shot, the following indicators were defi ned as the specifi c sum of the length of cracks PPM in the body simulator at a depth of 1 cm, the presence or absence of diphenylamine, the presence or absence of soot, the specifi c sum of the length of cracks TCLM in the body simulator at a depth of 3 cm, the relative concentration of lead and the presence or absence of clothing. Conclusions. Thus, on the basis of the features of damage formation of non-biological simulators of the human body and the «clothing + non-biological simulator of the human body» complex, as well as trace- forming elements of the structures of the «Fort 9R» and «Fort 17R» pistols when fi red from this weapon, reliable discriminative models were built as possibilities identifi cation of «Fort 9R» or «Fort 17R» pistols, as well as distances of shots at close range, from a distance of 25 cm or from a distance of 50 cm