We don't know it's a girl. You're speculating, wildly, that she has taken images of him without his consent. We don't actually know they've ever interacted in person.
It has been reported that the celebrity involved has at some point had possession of images of the child when they were 17. That is a criminal offence. IF they destroyed them when they knew the age of the child, that's potentially another defence, but it doesn't mean they haven't committed a criminal act.
You seem awfully invested in painting someone who was a child when this all started in the worst light possible. You're the one who's brought up only fans, too, which I haven't seen mentioned in the press anywhere.
Why are you so invested in defending this celebrity?
BTW, for those speculating about why the police aren't investigating- a) they may be, and can't comment at this time, and b) in my experience of teaching this age group, the police are very reluctant to get involved, even when there is clear suspicion something criminal has taken place. It's very messy, and has a low prosecution rate, so they don't want to "waste resources" on it.
Still doesn't mean it's not a crime.