News sources now report that the terror suspects might have been Chechen terrorists with military training. These same terrorist cells have been responsible for bombing and terrorist attacks against Russia. It is not clear why they would now target the U.S., except that they might be sympathetic to al Qaeda. President Putin of Russia is now open to offering the United States help with their crime investigation.
One Chechen terrorist in now dead, but 19 year old Dzhokhar A. Tsarnaev is still on the loose, with plenty of suspected terrorist military training.
Russia has had significant loss of life from Chechen terrorists, who have struck Russian civilians in their extremist warfare.