Kids as young as 15 were stripping on TikTok’s live feature fueled by adults who were paying for it.

That’s what TikTok learned when it launched an internal investigation after a report on Forbes. Officials at TikTok discovered that there was “a high” number of underage streamers receiving a “gift” or “coin” in exchange for stripping — real money converted into a digital currency often in the form of a plush toy or a flower.

This is one of several disturbing accounts that came to light in a trove of secret documents reviewed last week by NPR and Kentucky Public Radio. Even more troubling was that TikTok executives were acutely aware of the potential harm the app can cause teens, but appeared unconcerned.