I feel this is the very reason Julie Cutlers car ended up in the ocean. An attempt to destroy DNA in and around the vehicle. But DNA forensics was relatively new. UWA was just starting a course in DNA forensics. The mmmm Safe Community Fund I think it was actually paid for a DNA unit that was never used according Debi Marshall.
I would have thought your average crim wouldnt have known about DNA destruction at the time. I don't even think I knew about DNA at the time. But I didn't know much then. I was in a bubble.
Which begs the question. Someone must have had considerable training to be ahead of the game with future technology developing. What type of criminal knows this? Particular police units would have. Im not implying a cop. Someone would have some science education?
At that point, what level of education would have taught about DNA, how it would be destroyed and how to prevent its detection. That narrows down some POIs across the public
Police only have full DNA through a forensic link to the Karrakatta assault and that was an earlier crime. Notably the 2 discovered bodies didnt appear to shed any light on DNA but had a forensic link.
Some police investigators were not overly accepting of the new DNA technology. It was a game changer.
Our criminal has a university education? Maybe in science?
He left her for dead. It sounds like it was a violent sexual assault,not rape. Hard to tell with media artistic licence. But didn't he ponder his DNA would turn up? 1996 Spiers disappears.
Did he let her go deliberately? There was a forensic link. He must have been confident they wouldn't match his DNA unless they found him? He's regional or overseas?
Could it have been a brand new station wagon in 1995?