Can you guys help me find accounts of torture by torturers?

I’m in an excellent philosophy class called Torture and Dignity. We’re trying to figure out the phenomenological structure of human experience as revealed through torture. We’ve come up with a lot so far, but all of it is predicated on victims’ accounts of torture. Our primary source so far is this incredible book. But we’re not working with any accounts of torture by torturers, and this is where I think our exploration may be hitting a wall.

I guess the problem is that such accounts are devilishly hard to find. I’ve found a story by Gunter Grass about being in the SS as a teenager, and a fiction book by Gene Wolfe from the perspective of a torturer, but neither of these really gets down to business, in terms of anything that would suggest a phenomenology of pain. So, collective, will you help me out with your mad Google skills? Things written by rapists on rape and accounts by those who participated in genocide would also be welcome.

If you want to call me out for asking a homework question, fine… but this is not me trying to get you to do my work, just me trying to do more work than necessary and asking for help in the article search. I have no interest in plagiarizing your thoughts on torture.