3. Explosives Engineering Research

(conducted by expert Vinogradova T.V.)

To answer questions 1, 2, and 5 of the resolution, the expert studied materials from previous sections, the crime scene inspection report dated September 16, 1999, with appendices, video material filmed at the explosion site, the item inspection report dated September 20, 1999, with appendices, the interrogation report of suspect Iskanderov A.I., and the interrogation report of witness Iskanderova V.V.

As follows from the video recordings and the crime scene inspection report, in front of the 4th entrance of building No. 35 on Oktyabrskoye Shosse, there is a crater in the ground with a depth of 3.5 - 4 m and a diameter of 13.5 - 15 m. Also, within a radius of several hundred meters from the crater, glazing, window frames, and door frames in residential buildings and other structures were partially or completely destroyed. These destructions are the result of the action of an air shock wave formed during the explosion of a concentrated explosive charge. At the same time, the location of the crater corresponds to the location of the charge.

According to the crime scene inspection report dated 16.09.99 and the item inspection report dated 20.09.99, fragments of parts from GAZ-53 and PAZ-3205 vehicles were found at distances of up to 430 m from the crater. As seen from the presented photographs (appendix to the item inspection report), the found fragments have deformations characteristic of explosive impact. It follows from this that the explosive charge was located either in the immediate vicinity of the specified vehicles or inside them.

An assessment of the mass of the exploded charge was carried out based on the partial destruction of glazing recorded in the crime scene inspection report of building No. 56 on Koshevoy St., which was the most distant from the explosion site (about 700 m).

For the calculation, Sadovsky's formula for a surface explosion was used (Pokrovsky G. I. Explosion. M. "Nedra" Publishing House, 1973):

$$\Delta P = 1.06 \cdot \left(\sqrt[3]{G} / R\right) + 4.3 \cdot \left(\sqrt[3]{G^2} / R^2\right) + 14 \cdot (G / R^3), \text{ where (1)}$$

• $\Delta P$ - pressure jump at the shock wave front, atm;
• $G$ - mass of the explosive charge in TNT equivalent, kg;
• $R$ - distance from the explosion site to the object of interest.

Considering that for partial destruction of glazing, the value of $\Delta P$ must be at least 0.015 atm and no more than 0.02 atm, and solving equation (1) for $G$, we obtain an explosive charge mass in TNT equivalent of at least 800 kg and no more than 1850 kg. It is not possible to provide a more accurate assessment due to the expert's lack of information about the dimensions of the glass, the methods of their fastening in the frames, and the strength of the frames themselves.

The nature of the destruction and damage to the houses, as well as other surrounding objects, indicates that an explosion of a high explosive (HE) occurred in the form of detonation. To initiate detonation in a high explosive charge, an industrially or craft-made initiation device (ID) is required - an electric detonator or a blasting cap; therefore, in the design of the explosive