Hexogen is only available in one place in Russia - the FSB factory that produces the highly explosive material.  The FSB is the successor to the KGB.

We have seen the use of hexogen before in "Chechen" bombings.  See http://www.nationalreview.com/script/printpage.asp?ref=/comment/comment- satter043002.asp for the use of Hexogen in the 4 successful and 1 prevented apartment bombings prior to Putin's election.

"Besides the logic of the political situation in August, 1999 that suggested that only by provoking a war could the Yeltsin leadership retain their property and their power, the role of the Russian government in the bombings is suggested by the character of the explosions themselves.

The four bombings all had the same "handwriting" as attested to by the nature of the destruction, the way the buildings' concrete panels collapsed and the volume of the blast. In each case, the explosive was said to be hexogen and all four bombs were set to go off at night to inflict maximum casualties.

To do what they were accused of having done without expert assistance, however, Chechen terrorists would have needed to be able to organize nine explosions (the four that took place and the five that the Russian authorities claimed to have prevented) in widely separated cities in the space of two weeks. They also would have needed the ability to penetrate top-secret Russian-military factories or military units to obtain the hexogen."

Back to the present.  As a result of the planes going down, "Security analyst Andrei Soldatov said the reported Chechen connection could bring more suffering to the republic, where Russian forces are widely criticized for abusing and abducting civilians.

"The government will now be able to say that the fight against separatists in Chechnya comes under the roof of international terrorism. As soon as they say that, you can forget about human rights in the region," he said.

http://www.ledger-enquirer.com/mld/ledgerenquirer/9506740.htm