Roy23,
Only if you can link it to an intruder. Also to avoid confusion we should be told if Patsy's touch dna is on the longjohns, or even John's? We need to know this so we can take the foreign touch dna seriously. Also is there foreign touch dna on the waistband of the size-12's, is John's touch dna to be found there? Without these questions being answered, the foreign touch dna, does not mean much, not unless you wish to use it to exonerate the Ramsey's?
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UK,
Here is my point. Until it is linked to someone, because of all the other bungles from a variety of different things, enough reasonable doubt would exist that a conviction would be almost impossible. I am saying forget all the opinions that people here have, including me. I am just saying it doesn't matter who the DNA belongs to but until they find it, a killer would not be found guilty beyond a reasonable doubt short of a confession.
This DNA may be able to be explained away by some on this board, although I and whole lot of other experts would disagree, but it would still create enough reasonable doubt.