I posted an article on that topic in one of my follow-up posts in this thread. It is the post where I quote Litvinenko, the very last link in it.
I have a lot on my plate. Unless a guy like Nyquist makes an explicit and clear case for a specific conclusion, this kind of information goes under "file it," as but a potential data point. It certainly isn't enough to form an opinion. Insofar as whether Russia has taken action to support Islamic terrorist actions specifically against American interests as opposed to (for example) making a mess of over a billion violent eschatological idiots on their borders, well, I don't seen enough evidence of that here to make a conclusion given the strong potential for agitprop from a "former" Russian agent. He might be, he might not.