Traveller!
Did it again deleted my entire post drats. So to be terse now:
Sudgen believes that wall message which was written by Jacko,'The Juwes are The men that Will not
be Blamed for nothing. Upper case letters as given in PD report at the time but disputed by some. I quoted his foot note already. He moves through as an objective observer then adds a final opinion and in this case saying that chalk message was probably the only piece of real evidence the Ripper left behind! He does accept it as from the Rips' hand. Most experienced Ripper researchers believe it was written by the Ripper too.
Young Z (in my view) mentioned "female parts"in his '66 Confession. He did cut Bate's throat twice almost decapitating her.Then sending the letter itself was like what had been written about the Ripper in the 50's-60's period. It was later found by Sugden and others that Jack probably didn't write most if not all of the letters ascribed to him; Z had no way of knowing this,and this may have influenced him to write letters,etc. Even the bloody apron worn by one of the Rippers victims ( he had to have carried there and dropped it near the message-it fit perfectly with the missing section of the vicitim's apron) and found very near the wall message that night in Mitres Square(JTR claimed two victims that night all within an hour or so!) was like the Stine bloody shirt or this may have inspired Z. As per Dave Peterson Z expert witches did send 'bloody cloths' to threaten and scare their enemies. Zodiac seemed to be into the occult.
The from hell missive addresses to Lusk is probably the only one he did write, but even this is contraversial.