Apparently Ivan Milat killed when he was either single or had a relationship that was ending- and could control himself (as far as murder went) while in a relationship.
http://www.news.com.au/national/pet...7s-eighth-victim/story-fncynjr2-1226683152792
So maybe the CSK has similar power and control issues- maybe he had suffered a relationship breakdown, that was either rekindled or he met someone else.
Or, to add another possibility- he was and still is local, but is a frequent traveler, for either leisure or business. We cant find similar cases because we are looking in Australia.
I havent been able to find an exact date for Mark Dixie arriving in Perth, however he seems unlikely to me. He seems pretty volatile and out of control. When he killed in Britain, he left the body of his victim where he killed her. He was caught because he got into a pub fight, and his dna was taken.
https://en.wikipedia.org/wiki/Mark_Dixie