how to expose someone...he showed us a pic of his Dick?

[alana]

Soo I'm in this fb group. It's for teenager girls for a group called mindless behavior. This grown person telling people to add him,kik people (got their kik names from the group wall),and showing us pictures of his Dick. I looked at his fb and it says "im hard" at every single status at different dates. He deleted the picture but keep kiking girls pictures of his dick. Like im barely 14.i.dont wanna see that. If I.wanna porn I go on pornhub or google it. The girls range from 11-17 it mostly the older girls on.since it's night. What to do?.how do we expose him. He is GROWN. I have screenshots. Sorry for typos im typing fast on a touchscreen.