As more information on the origin of the alleged perpetrators is coming to light, I am concerned to note in the social media a most unfortunate misunderstanding in this respect. The Czech Republic and Chechnya are two very different entities - the Czech Republic is a Central European country; Chechnya is a part of the Russian Federation.
It says something about both social media and American life, I fear, that the Czech embassy actually felt it had to release a formal statement devoted to it.
What really worries me is that there might be Americans who would read the last sentence above and think, "But aren't Central European countries part of the Russian Federation?"