In February 2003, Kommersant journalist studied the criminal investigation file on the Ryazan incident, obtained by Russian State Duma member Sergei Kovalev. According to the proceedings, a bomb disposal expert who arrived to the scene had twice performed a test which didn't show the presence of explosive particles. The head of the bomb squad Tkachenko, who arrived soon after that, made a test himself and found the RDX. The investigator who questioned Yuri Tkachenko concluded that the detection of RDX was made possible by contamination of Yuri Tkachenko's hands, since the latter worked with explosives containing RDX on the day before the incident without wearing sterile gloves. Another detail concerned the type of a device used to detect the explosives. The report submitted by the Ryazan UFSB claimed that gas analyser "M-02" was used. However, during Tkachenko's questioning it was revealed that he had used the device "Exprel" for the analysis. The investigation has resolved the contradiction in the following way. The bomb squad in Ryazan is equipped with the gas analyser "М-02", but the latter has certain limitations. The device has a high degree of imprecision, and the analysis takes a long time. So, the bomb squad used the device "Exprel", which is more robust, accurate and easy to use. But since they were not supposed to possess that device, the bomb squad has submitted the paperwork which showed that the gas analyser "M-02" had been used.
