Someone already speculated as to this, but I'm really starting to wonder if Jerry is the Scar. The "thick hair" is, of course, wrong, but they both have the same gesture of running their hands through their hair (or former hair, as the case may be); there are the ties to Australia; and they are both in Europe right now. The part that doesn't make sense is why he'd wait until the boys returned to the US to have them assassinated. Surely it'd be a lot easier to accomplish in a remote part of Australia. And the motive isn't clear...well hidden resentment over their treatment of Lump? Or is he using their equipment somehow, which makes them another loose end? On the other hand, maybe this is all a crazy conspiracy theory and I should just sit back and enjoy the story.