Find the Lost is opengenus project. It has the aim of creating APIs to track lost people.
I am having the same purpose to control child trafficking, find missing kids etc.
For the implementation, I was wondering if we should create a website (and app) where anyone like you and me can upload the photo and location detail of children roaming around railway stations, bus stations etc. as a beggar. On the other side parents can upload the photo of their missing kids. Our face matching algorithm can notify them as soon as we find any matching face.
Any inquiry will be invalidated after a certain period until the user keep it active.
Your contribution in terms of development, system design, technology advice, legal issues etc. will be helpful to make this project live.