[Kuruharan]

Hence it may be concluded that living being with a tool attacking one does not necessarily need to be anything but 'twisted' kelvar.

Yes, but this reasoning is more complicated than just thinking, “Hey, these creatures might be sentient” (partially because it requires a realization of sentience before you can move to this next step).

Besides, when lone is attacked by many, even if it was an accident, from the lone's point of view it would be 'malice aforethought'

I think too much is made of this “lone” business. There are a couple of points here. A) I don’t think the Petty-Dwarves would have attacked Elves in the first place unless they were in a position of great superiority (I think we can probably all agree on that) B) On the other hand, if the Elf was really alone or even if there were a few of them, there would not likely be any survivors to say who did it. There would not be any reason to think it was Petty-Dwarves or anybody else (unless they found footprints, which would look suspiciously like smaller versions of their own feet…hmmm…) Having survivors implies a larger group of Elves, which requires a larger group of Petty-Dwarves, which requires greater organization on the part of the Petty-Dwarves. This should have been telling to the Elves.

petty-dwarf hunting could not have possibly occurred more than couple of times at all.

That was pretty much my impression.

And about chimps - it seems they are capable of building tools, after all

Didn’t I say that?