I give up with a serious suspect, Heller is leading us all on a wild goose chase, and i'm getting fed up of suspecting everyone shown onscreen. 

So, i'm going to be silly. We know RJ is basically another version of PJ, so lets assume that he too is australian. We know that he has great hunting instincts, is skilled outdoors and is very good with a knife.


At the end of "Red Sky in the Morning", we see that RJ kills the copycats in a very skilled manner, almost as if he's saying "That's not how you kill someone mate, this is how you kill someone"

RJ is Crocodile Dundee