This is the most up-to-date, detailed and thoroughly-researched survey of the two crises currently available in English. What it makes clear, beyond reasonable doubt, is that both tragic events were aggravated - and their consequences made considerably worse in terms of loss of human life - by Russian federal state intervention, and that Russian special services, above all the FSB, were involved in collaboration with the terrorists.
Of Dubrovka, the study concludes:
Elements among both the Russian leadership and the power ministries and among the Chechen extremists obtained their principal goals in the assault on the theater at Dubrovka: namely, an end was put to the negotiation process while Aslan Maskhadov's reputation was besmirched, and the terrorists, for their part, had an opportunity to stage a grandiose fund-raiser. The Russian authorities, moreover, were now able to demonstrate to the entire world that Moscow, too, had been a victim of an Al-Qaeda-style Chechen terrorist act. As in 1999, the chief victims of these terrorist acts were the average citizens of Moscow. The bulk of the evidence, as we have seen, points to significant collusion having occurred on the part of the Chechen extremists and elements of the Russian leadership in the carrying out of the Dubrovka events.