First thing I would say is support the child.

Make sure the child knows that you're there, that you're going to help them through this, that this is in no way their fault.

That applies whether it's AI generated or not.

Even if they've in any way been involved in the creation, they need to know that this is not their fault and they're going to be supported through it.

Don't punish them in any way, like by saying you shouldn't have been on your phone anyway, anything like that, because this isn't the child's fault and they need support.

Secondly, as I say, contact law enforcement.

Even if it's not an emergency, you then contact them via the non-emergency channels.

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