even without the shawl as evidence, Aaron Kosminski was still considered to be a suspect because he supposedly worked in the same workhouse that some of the victims had been working at.  if his motive was revenge for having been given syphilis by one of these workers, that would be sufficient motive.  however, there are numerous extenuating factors that need to be addressed and taken into consideration.  i'm not saying that it couldn't have been him, but we would then have to presuppose both vampirism and cannibalism as additional motivating factors in the murders.  Polly Ann Nichols was almost completely drained of blood, and the doctor that arrived on the scene took note of this not to mention that she was probably still alive when first discovered and the killer (on this occasion working alone) was hiding in the shadows.  the first police officer to arrive on the scene noticed a small amount of blood coming out of her neck wound.  which could theoretically have been made with a barber's straight razor.  why did it look like Polly Nichols was sleeping when she was first discovered??  and why did it look like she had just been murdered with her eyes popped wide open when the first police officer arrived on the scene??  and why did the killer suck a gallon of blood out of her neck like a vampire??  before the police officer arrived on the scene.  one witness claimed to have seen Elizabeth Stride (the other woman murdered by Jack The Ripper the same night as Catherine Eddowes) in the company of a well-dressed gentleman and that this well-dressed gentleman bought her a bunch of grapes and a box of sweets.  she was found with this bunch of grapes and box of sweets resting on her stomach by the first witnesses.  but then someone stole this evidence before the police got there.  maybe Aaron was a polymath who could also speak in German as well as being able to write in English (using special knowledge only known to the Freemasons).  but he would have to have had an accomplice:  a carriage driver.  other witnesses claimed to have seen someone dressed up as a sailor or a theatrical pirate stalking both Elizabeth Stride and Catherine Eddowes.  no matter how good the theory, there is no 100% proof of who did it.  also, how long did the shawl stay in the police evidence room at Scotland Yard before being returned to the family of Catherine Eddowes??  and wouldn't the family have washed the shawl several times to wash the blood out??  are you saying there was still mitochondrial DNA evidence after all of that being done 100 years or more later??  i'm not ruling out Aaron Kominski as a suspect, i'm just saying that what you have is not 100% proof as you claim.  if he was working at a workhouse with these women, how could he have also been working as a barber??  or was he forced to work at the workhouse because his barber business was slow??  but then how could he have afforded the grapes and the box of sweets given to Elizabeth Stride??  these questions have to be addressed and answered.  was Aaron Kosminski poor or was he rich??  if he was rich, why would he be working at a workhouse along with the other poor people??  was he a polymath or a poor idiot??  if he was suffering from dissociative identity disorder, maybe it is possible that he was both.  a kind of Dr. Jekyll & Mr. Hyde type??