"It is commonly accepted by the experts on the case that none of the letters purported to have been written by the Ripper were in fact written by him."
This may not be a good way to prove the case after all.
http://www.casebook.org/intro.html
This may not be a good way to prove the case after all.
However, if the DNA evidence from the letters can be linked to one of the suspects, it would change a lot of things.