artists_beware | Advice on Tracing/Heavily Referencing (Reply)

I'm sorry if this is the incorrect community to post to, but I'm at a lost of where to turn, and it seems that Artist_Beware give good advice to artists.
I've been quite unsure if I've actually wanted to come public with this either, just attaching my name feels like someone will find out it is me. I'm afraid this might ruin my standing in the community because this person is popular, but I hope this post is worth the risk.

TLDR; I suspect someone, who has been caught tracing before, is continuing to do so. But the sources this person is tracing from are INCREDIBLY hard to find (see reasons below).
This person takes commissions, if that matters at all.
What do I do to help put a stop to this? Are there places I can post (anonymously) about this issue in hopes more people can look for sources? Should I directly confront this person, or should I continue to go through administrative routes as I have done in the past?

This person is popular on the site I post on, and because the images they choose to trace from are so obscure and hard to find, no one knows what they are doing except the staff and I.
The first red flag to me was that this person's work quality seemed to jump from image, to image. I didn't think anything of it for a couple months, until I came across several images I KNOW I had seen before.
This prompted me to look for the original images. I did in fact find the original images. The original images were in the middle of my favorite manga. In the middle of a chapter. I just happened to read this manga SO MANY TIMES that I had noticed the similarities.
Now this search wasn't easy. The manga has about 80 chapters, and I went through every single page to find these. It was time consuming, and I had to go back and forth several times to find them. However when I did find them the images lined up pretty well. Let's just say they lined up well enough that I reported the stolen images and the staff took them down. None of the images that where taken down where commissioned pieces, however looking at several other pieces I could see the jump in quality.
The staff had told me if I could find one more traced piece this user would no longer be allowed to post on their site. I have spent many hours pouring over websites, mangas, anywhere to see if I can find something else.
The problem is that this person changes the colors so well/lineart is a different quality that I can't just throw it into tineye or any website like it. I'd need to know the exact location of the image to find it.

The part that bothers me the most is that none of this is public knowledge and this person continues to take commissions. None of this person's clients are aware of this, since I went directly to the staff and the images were removed with out mention to anyone. To be fair, it looks like this person hasn't posted a commission in awhile, however I know people have paid this person for work to come.
All I know is that I wouldn't want to be in a clients shoes where my piece MAY or MAY NOT be traced.

I don't know where to turn or what to do. Maybe I'm spending too much time on this person.