This is a bad situation in so many ways... but there is hope.
Be smart and be careful. People could literally go to jail, lose their jobs, etc. It sounds like some of those could be family members. If that happens, then those people will possibly come after you. If you do anything / report anything to the authorities do so anonymously. Keep yourself out of it. But that said, seeing what you have said you saw- if this is true, it is a sad state of humanity and you owe it to yourself to take some kind of action, even if passive.
My suggestion- just post the location /name of where this is happening in this thread and then walk away from it- I can assure you that something will happen- and you will have plausible deniability because you can never be sure if it happened because of this, or maybe someone else happened to see the same things and reported it. Your conscious with your family is clear.