If the case papers are anything to go by, the finding of a condom so close to the murder scene had them pretty convinced before the DNA results came back. But the nature of the investigation into the condoms (there was another found in a cave about 500 yards away) is telling.
In the first instance, they tried to distance the first condom from the murder by expanding the distance from 20 yards, to "within a 20 yard radius" to "within 50 yards." They didn't say, for example, that the blood stained branch was found "within 12 metres" - it was 12 metres west of the body. They didn't say Jodi's spectacles were found "within 3 metres" - they were 2.7 metres east of the body. The only reason I can think of for the lack of precision about where the condom was found was that they wanted to make it seem "too far away" to be of any importance. But why would they do that, especially if they believed the murder to have been sexually motivated and the DNA donor had not been traced?
Oh yes, I forgot - because the donor was not Luke and they needed him to be Luke.
The first DNA results were received 12 days into the investigation - at that point, they would have received the news that the contents of the condom did not originate from Luke. Rather than drop the connection right there, however, they tried to connect that condom with the condom found in the bin in Luke's room. Why? Who knows - a bit like the so-called knife evidence, so that they could say "a condom of the same brand as the one found in the bin in Luke Mitchell's bedroom was also found near the murder scene?"
The condom in the cave is just plain strange. The DNA profile from it was listed in the DNA reports as "unknown male" (it was a full profile). But they traced the two vagrants who had been living in the cave and got DNA profiles from them. However, the DNA results were not amended to link the DNA of either vagrant with the DNA from the condom. So.... if it didn't belong to either of the vagrants, isn't it a least possible they got the wrong flipping vagrants???
The media happily advised us all that the vagrants had been traced and eliminated. What they didn't say was that the originator of the condom contents had NOT been traced or eliminated.
By the end of the first week, the FLO was telling Luke and his family that Jodi had not been sexually assaulted (I guess, in her defence, the presence of sperm heads and semen deposits all over her body and clothing hadn't been recorded in the forensic report by then).The same day, the media broke the story that Jodi may have disturbed someone committing a sex act in the woods. So whoever was leaking information to the media knew (or had a damn good idea) that the sperm and semen deposits were not likely to come back from the labs identifying Luke - after all, the deposits were known about from the off - stains testing positive for semen, etc. I don't believe for a moment that senior officers sat twiddling their thumbs for 12 days saying, "It's ok, we'll just wait for the lab reports" - not a chance. I believe there has to have been contact throughout.
In fact, I know of another case where the Senior officer was emailing and calling a contact at the labs repeatedly, suggesting they use a specific technique on a specific sample from a specific area on a specific article of clothing. It took months - the lab kept coming back saying there was no point, the chances of a strong profile were miniscule, the technique in question did not provide as reliable results as other methods, there were better samples on other articles of clothing, etc, but eventually, after months of pressure from this officer, they agreed. (Direct funding had also been refused, so the agreement to test in this particular manner was on a "non urgent," when they could get around to it basis. Bet nobody can guess the outcome??
Yup, miraculously, they found a "full" DNA match (well, not quite, but it was close enough and they provided a plausible explanation for the missing bits!) Interestingly this "match" was found from a tiny group of cells lifted from a tape which had somehow acquired a mysterious cut... the cells were right next to this mysterious cut (which sliced right through both top and bottom layers of tape "sandwiching" the sample between them). The expert asked to comment on this said it was, in her opinion, highly unlikely that any contamination of the sample, via the mysterious cut, could have occurred.
Sorry to digress, but I think it's an important point - the labs testing these deposits are far from "independent" - they are aware of where their money comes from and if a senior officer calls up looking for a heads up before all the results are available, are they really going to refuse?