In January, US Sen McCain went to Syria to meet the rebel factions.
Who? What we now know as Islamic State (well the US was best friend with Saddam after all).
The picture was from CNN (now as IS PR document) where Sen McCain was saying to be very moved to meet this fighters).
So now you can keep on wandering how come Islamic State is so well trained and weaponized.
Look for the usual spot. If they are not Russian, they are the other (at least the Russian seems to know where their weapons end up)