Its actually making sure there's no incriminating evidence.
Could one of the major players have deliberately done this, yes, is it likely, NO! To much potential blow back if it ever came out who was behind this.
Could one of the major players have accidentally done this, yes, is it likely, yes! Even well trained armed forces have done it.
So the question is what system was it, and what level of training and support was actually needed to operate the system. There is no doubt Russia has advisors in the area, and others actually running things, the question is, did they have them helping out with that particular system.
It is no secret that the rebels have been pushed back lately, and as a result material support increasing to them. The simple fact is, nobody on the Rebel or Russian side (the players) will give a sh!t about a couple of hundred people, its war.
What they will give a sh!t about, is the
PR and potential fallout.