The statement mentions U.S. media reports that one of the Tsarnaev brothers -- the two suspects in the Boston Marathon bombings -- spent six months in Daghestan last year and may have tried to make contact with insurgency representatives but did not explicitly deny that he succeeded.
Even before the posting of that disavowal, there were several reasons why the possibility that the brothers acted at the behest of the North Caucasus insurgency was arguably the least plausible of the various hypotheses regarding their motivation and ideological affiliation.
The first is that the insurgency had no motive whatsoever to attack the United States, especially given that Washington has reportedly just added Chechen Republic head Ramzan Kadyrov’s name to the Magnitsky list of people sanctioned by the U.S. government and banned from entering the United States.
As the vDagestan statement noted, the insurgency considers Russia its primary enemy in light of its "occupation of the Caucasus and monstrous crimes against Muslims." But even so, the vDagestan statement pointed out, self-styled insurgency leader Doku Umarov issued a moratorium one year ago on attacking Russian civilians.
The second is that the modus operandi of the Boston terrorists diverged from that employed by the North Caucasus insurgency in the mass-scale attacks it perpetrated prior to Umarov’s ban on targeting Russian civilians.
In the case of the Moscow metro bombings in March 2010 and the Domodedovo Airport suicide bombing in January 2011, the blasts took place in a confined space, not in the open air, with the explicit intent of inflicting the maximum number of fatalities and at the cost of the perpetrators’ lives. By contrast, the Boston blasts were amateurish.
Third, if the North Caucasus insurgency had perpetrated the Boston attack to generate publicity, a video address by Umarov would most likely have been prepared beforehand and posted on the Internet within days of the blast, as was the case in the Moscow metro and Domodedovo attacks.
Fourth, even though Tamerlan Tsarnaev reportedly spent six months travelling in Daghestan and Chechnya last year, it is not easy for would-be recruits to establish contact with the insurgency in urban areas. True, the Daghestani insurgency websites offer any amount of advice to would-be recruits, from how to increase your physical fitness and stamina to how to prepare psychologically and even the best sort of boots, rucksack, and battle fatigues to buy.
BACKGROUND: Analyst Liz Fuller's 2010 overview of websites linked with the North Caucasus insurgency
But, out of elementary security considerations, in order to minimize the ever-present danger of infiltration by Russia's Federal Security Service (FSB), they do not offer any indication of how to make contact. Instead, they imply that if you are regarded as a potential asset, a recruiter at one of the Makhachkala mosques will vet your background and then, if you are deemed suitable, approach you.
Russian media have reported several instances of young men from elsewhere in the Russian Federation who travelled to Makhachkala with the intention of joining the jihad and landed directly in the clutches of the security services.
As noted above, the leadership of the Daghestani insurgency wing does not explicitly deny that Tamerlan Tsarnaev sought to make contact. It is very possible that in light of his reported interest in the insurgency and monitoring of insurgency websites he may have tried to do so, but could have been rebuffed.