The work on the DNA proved the provenance of the shawl. Or do you think it is a coincidence that the blood of the last victim and DNA of Kosminski are found on the same garment?
I think they claimed that. mDNA can't tell the whole story and that's all they mentioned. I question, because they didn't say, what the quality of the samples were. They have no way of knowing the history of the shawl. They don't mentioned how or when or who they collected "family" samples were. What do they mean by "identical match"? In the world of DNA, unless you have two perfect samples from the same person, there is no such thing as an "identical" match, so what exactly do they mean? Identical mDNA ONLY means that at some point in the past two people shared a common ancestor (see Mitchochondrial Eve, the common ancestor of every living human). Too many unanswered questions.
Right now it's unclear what they mean, what's coincidence, what's good work, etc..
And do you really think that Drs. David Miller and Jari Louhelainen will put their professional reputations at risk so that Mr. Edwards can sell his book? Really!
People do it all the time. Google scholar shows no public works, no major citations, nothing notable in his career at all. His work isn't peer reviwed and he hasn't disclosed any details regarding his samples, his methodology or anything. Other than this, he really has no reputation.
But, as trusting as you are, I have some oceanfront property in Iowa to sell you. It's got water and sand, totes legit. You interested?