Here goes content of that letter:

Dear Boss,

I keep on hearing the police have caught me but they wont fix me just yet. I have laughed when they look so clever and talk about being on the right track. That joke about Leather Apron gave me real fits. I am down on whores and I shant quit ripping them till I do get buckled. Grand work the last job was. I gave the lady no time to squeal. How can they catch me now. I love my work and want to start again. You will soon hear of me with my funny little games. I saved some of the proper red stuff in a ginger beer bottle over the last job to write with but it went thick like glue and I can't use it. Red ink is fit enough I hope ha. ha. The next job I do I shall clip the ladys ears off and send to the police officers just for jolly wouldn't you. Keep this letter back till I do a bit more work, and then give it out straight. My knife's so nice and sharp I want to get to work right away if I get a chance. Good Luck.

Yours truly

Jack the Ripper

Dont mind me giving the trade name.

PS: Wasnt good enough to post this before I got all the red ink off my hands curse it No luck yet. They say I'm a doctor now. ha ha.