Yes, I read that article too. But, the example given in both articles was the same: DNA being transferred from one garment to another within a single load of laundry. That makes sense to me and, imo jmo, has a much higher statistical probability than having BK's DNA left behind in a washer and deposited in the next person's laundry, and that person just happens to actually be the killer.
Or for an even more exotic scenario, that BK's DNA lingered in a public machine through numerous loads washed by different people, to finally be deposited on a load the killer did, and the killer somehow transferred BK's DNA from his/her clothes to the sheath just before he/she committed the murders. IMO, one of us is more likely to win the lottery. MOOooo and would love to hear 10ofRods (or someone else with a good statistical mind) thoughts on how possible either scenario might be.
I think that scenario is very unlikely,
as then it would not be single source DNA as reported in the PCA. The person depositing the DNA on the snap would leave their own DNA (as well as DNA from all the other people who used that same washing machine recently). No washing machines would have just BK's DNA in it. The deposit had to be done before the murders, as well. So it was all ordinary loads of washing.
The odds of another person washing their clothes immediately after BK washing his, themselves wearing gloves and a mask all throughout their laundry process (!), are very remote. Because that person would get their DNA on the sheath, too.
But they didn't.
I believe that the cells from which the snap DNA came were in the groove around the edge of the snap (and would be found in adequate amounts in the nearby leather, which cannot be tested without destroying that bit of leather). I believe it took many (let's say more than 20) openings and shuttings of the snap with an ungloved finger or thumb to leave that DNA.
Just keep in mind that every washing machine would have DNA from the various people who used it - never just BK's. No way for someone without expensive scientific equipment right there in the laundry room to be able to extract just BK's DNA from a washing machine (and why someone would even try that, is beyond me). Someone attempting to extract just one person's DNA from their own previously washed clothing would need an entire lab and, IMO, full access to said lab such as given only to forensic investigators and professors engaged in research, IMO. DNA processing labs are in special rooms with negative pressure and all of that, otherwise even more random DNA would be entering the study area.
Someone sneaking into such a lab at night with their laundry is absurd to me, but again, it would have to be someone who knows how to extra DNA (and they could not possibly have known whose DNA it was from this procedure - in that case, BK's DNA would be randomly chosen, replicated, and put on the sheath by a mad scientist).
IMO. And this is why the other evidence is equally important - although I know people love arcane theories, this one is beyond my own threshold of belief.