I promise not to bore you with a long write. Please be patient with me as I am still typing

Late last year, I got employed in the hospitality sector which was earned based on an interview. A month after I was employed, being intelligent, I got to understand the astronomical level of fraud going on in my department and others.

Because it was my first time working in the hospitality sector, I asked a friend what I could do. if I should expose them or close my eyes as if I saw nothing. He advised that I report but with concrete evidence.

Unknowingly to me, those guys already saw me as someone who isn't part of their scheme and was already planning on a way to push me out of the job.This was because the front office supervisor told them i got my employment through a connect from the top. Then They started giving me issues.

The fraud ring comprised of the supervisors and other regular staff (some who have stayed long in the hotel).

During this period, fortunately, one of them did the usual abracadabra. I didn't hesitate to report the issue. he was asked to bring his statement of account but he never returned. He left the job.

How they got to know I was the one that reported baffled me for months.
I now know how they got to know. "whatever happens at the front office stays at the front office"... "except a mole leaks the info". I was the mole

Due to the fact that those guys were much and I was the new folk on the block, they instigated alot of people against me and I really felt the heat. But somehow, I fought through that phase.

Now for some months now, I observed the head of all the supervisors has been instigating the security guys against me and a man who is like a right-hand.

I have never disrespected or disregarded the man before only for this man to hit me on my head. That's a physical abuse. Deep down in me I wanted to over power him and teach him a lesson but then again, I don't want to leave with a record of fighting.

For people who might say maybe he was playing with me, no it wasn't a play. As a matter of fact, the next shift when I resumed, he promised to stab me with bottle. This is a person I didn't have sex with his wife o... I didn't even collect his girlfriend or piece of land.
My issue now is I want to quit because I can't take this level of unprofessional abuse. If I report the man to the person that brought me in, my fear is I may be tagged as too problematic.
Someone once made a statement that everyone can't just have issues with me, that I have to actually be the problem. But how do I explain to the person that someone I didn't behave badly too or disrespected is promising to bring me to disrepute.

My issue now is, it's not like I have any other engagement I'll be moving to but I want to leave without being ungrateful to the person through whom I got the job.

When drafting my resignation letter, should I just state a simpler reason why I am leaving or I should write everything about the physical abuse by the man even if nothing will be done at least to protect other staff.

I am not the first staff he will abuse physically he has done it before.
If I continue there I am certain something bad will probably happen.