The burden of proof is on YOU to prove that your claim is true when you state it as some kind of factual thing, not someone else to prove that its not. He doesn't need to prove that they were not killed and tortured as a result of our "torture" until you somehow attempt to prove that it was caused by that.
Torture and killing was pepetrated by these people PRIOR to anything about Abu Ghraib coming out. Did they magically have a crystal ball that saw into the future? Or is it more that this is what these people do and they will use whatever current topic is useful to them for their propoganda to do it. Be it Israel, be it "occupation", be it "torture".