It looks like these two brave whistleblowers of a pedo ring involving high up people there were murdered some years ago.
https://news.sky.com/story/was-man-murdered-for-exposing-paedophile-ring-10368317
I'm sure if you begin looking into this, they will start popping up. I found that case pretty quick.
I'm so hopeful for a safe outcome for your niece. The more I've looked into the "system" and how they care for children, no child should go through that.