Reddit mentions of The Angel of Vengeance- Most Sadistic Series on the Market (A Glimpse into Hell Book 1)

They're pretty good. It's been a long time since I'd read them, but I remember the series being pretty good. If you want more disturbing type novels, check out J.F. Gonzales' Survivor, Wade Garrett's Glimpse into Hell series, and any of Matt Shaw's novels (although these tend to be rather short, but enSICKlopedia is a good length and contains multiple stories). They're disturbing on a total different level than Edward Lee though, with Survivor being the more tame of the ones I've mentioned.