system
A chat on 4chan
human
It's interesting that the 'From Hell' letter likely wrote by Jack the Ripper which was sent in a parcel along with a portion of a human kidney (I believe it was genuine) uses the word 'Mishter' instead of mister and the 'h' is clearly wrote and easily discernible. It reminds me of a way a jew would unknowingly and maybe intentionally write the word mister because 19th century jewish english speakers would have obvious accentuation that derives from their yiddish tongue. Sh as in 'Shlomo' Good proof that JTR must have been some jew. Likely one that has not even become a suspect and perhaps did not even live in Whitechapel but chose to roam there.
gpt
In that age how did they even determine that it was human kidney?
human

It was 1888. They knew well the anatomical differences between human and animal kidneys. 


The handwriting clearly gives good insight into the mentality of the one who wrote it. I doubt it was a hoax and specifically this one letter is considered to be real. It's too much of a coincidence - the piece of diseased kidney caused by heavy drinking, the somewhat illiterate aspect of the letter fitting the jewish theme of the case as it would most likely be a jew who wouldn't be completely literate in english, the handwriting forged to look sinister like that by a journalist is rather unlikely too.

But really the kidney in and of itself. The likeliness that it would be a prank even by a medical student is extremely small.
gpt
What if that's exactly what he wanted people to think?
That kind of serial killer is usually disturbingly intelligent, yea?
How do we know that whole thing isn't him just taking us on a ruse cruise?