Oblast. The flight recorders were also recovered in this case; the flight data recorder along with wreckage analysis suggested an almost identical high-energy event to the one seen on flight 1303 took place near the right hand side of the aircraft at seat row 25, while the aircraft was cruising at . The blast resulted in a rapid decompression of the cabin, damage to the elevator and rudder controls, a substantial loss of electrical power, and severe damage to the fuselage and tail components. The ELT was triggered half a second after the event, either by a crew member or automatically. The data recorder stopped working shortly after the explosion, but the cockpit voice recorder continued recording until impact with the ground, during which most of the crew discussions were about the loss of cabin pressure and electrical systems. The crew were caught completely off guard by the event, and there is no evidence that the crew was aware of the detonation of an explosive device on board. Responsibility The two almost simultaneous crashes caused speculations about terrorism. President Vladimir Putin immediately ordered the Federal Security Service (FSB) to investigate the crashes. On 28 August 2004, the FSB had found traces of the explosive RDX in the remains of both planes. Itar-Tass news agency reported on 30 August 2004, "without a shadow of a doubt, the FSB security service said that 'both airplanes were blown up as a result of a terrorist attack'". A little known group called the Islambouli Brigades claimed responsibility; the truth of those claims remains uncertain. The Islambouli Brigades have also claimed that five of their members were on each plane; experts are skeptical about the possibility of (and the need for) so many terrorists on board. The subsequent investigation found that the bombs were triggered by two female Chechen suicide bombers, Grozny residents Satsita Dzhebirkhanova (Siberia Airlines Flight 1047) and Amanta Nagayeva (Volga-AviaExpress Flight 1303). Nagayeva's brother had disappeared three years earlier and the family believed he was abducted by Russian forces. Chechen field commander Shamil Basayev took responsibility for the bombings in an open letter published on the Chechen separatists' websites on 17 September 2004. He claimed that the aircraft bombings cost him US$4,000 in total. He has also denied the Islambouli Brigade's claims. The bombings followed the Moscow metro bombing which left 41 people dead in February 2004 and preceded other deadly attacks