It's your responsibility as a concerned citizen to make them aware of this problem and also help them track where that video originated from. Maybe when you show them that video, they'll be able to know where it was recorded. My first guess being one of those shady hotels they must have visited which are notorious for doing such things. Also, do tell them to raise awareness and file an FIR against the Hotel owner( If they are able to find it).

Speaking from experience, I encountered a pedophile on Dark Web, when I was looking to buy some weed there. To my utter shock, the guy in the picture was one of my college batch mates and the girl was his minor sister. I reported the incident to his father and mother and they sent him to mental rehabilitation centre.

If you ever find something wrong, do report it.