---
Near the end, I noticed one or two hints that SCP-4987 was still around. I thought that was going to be the key to the solution at the end, but the story went for the more generic option.
I found a comment by QNTM that the former was actually his original plan[0]. Personally I actually would have preferred that ending but maybe that's just because I thought I'd guessed the twist ahead of time. The whole book is really really good.
If anyone comes into this not having heard of the "SCP Foundation" before, imagine something a bit like the secret government organisation from Men In Black but instead of aliens it's the paranormal.
[0] Major spoilers here if you haven't read the story already: https://scp-wiki.wikidot.com/forum/t-13410227/tombstone#post...