You could report him to the police. If he has joint custody, it would be supervised visits only if he's a sex offender so he's committed an offense by having her without supervision. I would act in favor of the child's welfare and not his in this situation.
Also, if the child was on a supervised visit with him and he left her with you then that is also a violation. You would not be at fault unless you didn't report him taking her.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.