Yes they have PS DNA on file, but not every murder victim had DNA found on them, or if so it may have been lost. Most of these cases are before they understood DNA and therefore they only tested saliva, blood or semen for blood type, I think PS was a non secretor so I doubt they were able to even get his blood group, however being a non secretor may well have narrowed down the suspect than blood group since there's significantly less people who fit in that category.
We can only say unsolved murders may have been killed by the unknown perp that killed Eve and Lynn if no DNA was found on them or wasn't recovered or kept in storage etc in a way he is more easily linked to unsolved murder cases in and borderline London area than Peter Sutcliffe who despite travelling to London for work, to visit his wife when she studied here and any possible events he may have attended, the murder would have to fit into those windows of opportunity, as yet I don't think a single London murder has been proven to be linked to him, just suspected. Even more likely to have been committed by him are girls, young ladies hitchhiking from London to Northern England.
Our perp in this case is vicious enough that both his proven victims were felt to be probably PS victims by a great many people. Therefore I look at people who match in a significant way those two victims, or that people may have suspected PS of killing. My thoughts are that you can't be too rigid in saying what someone will do, especially when the perp themselves has proven to be flexible in the way they have treated or chosen a victim, plus many criminals in whatever their criminal activity, will often when presented with the opportunity in their chosen field to go ahead with something which may not be exactly what they want, will seize that opportunity if it satisfies and they think they can get away with it.
For instance maybe a killer will usually stalk a victim, watch them, build up an idea when they'll be in a certain place and alone etc and yet they're walking home from the pub and there's someone who fits or semi fits into their ideal victim, they are alone and turn down a dark alley or lonely street with no houses... giving the opportunity to follow and see where it takes them.
The other thing is through these cases being so long ago is that, especially if there is no family to push for public appeals or police reviews, details can be lost or confused. At least one of the ladies that was thought to be by killed by the same person as Eve and Lynn is Lynda Farrow, who had a lot in common with Eve as well as living very close, but there are conflicting reports if there was DNA or not, so we don't know if our mystery perp can be ruled out. Also the police, a big part of looking at murderers is what the motive may be and the fact she left her husband and moved in with her bf, pregnant with his child and there were custody issues of his daughters gave him motive to pay someone to kill her.
But few murder victims have their throat cut like Lynda and Eve, both blonde, both stunning, both working in the west end in high profile jobs and apparently both working as croupiers, both in close proximity and within a few years of each other.
