Are you looking for a double-blind experiment where in hundreds of randomly selected countries the civilians were slaughtered, in other hundreds they were not, and this was all conducted in a way that neither the people in the attacking countries nor the people in the attacked countries knew which was which?

No. I am looking for specific, reliable evidence which backs up Tsipursky's claim. It is up to him what form that evidence might take. Is that a problem for you?