Honestly, though, I don't have high hopes when it comes to these ransom attempts. If you give in, they will ask for more: the leverage is on their end and only increases every time they are paid. If this guy has these images, then they may as well already be in the public domain. Of course, the underage pictures are certainly illegal, but I don't think he will do something as stupid as post those to your friend's companies.
The "weird" in this case is that the blackmailer doesn't want money. He/ she/ they want more pics....
I also think it is someone that knows her, because he is trying to blackmail her for more pics/vids, which is weird to me.. He isn't asking for any kind of payment like $$ or BTC, but more pics..
You can call it "stupidity" but he can call it "cunningness", show her that he can do whatever he wants and no cost for his side. This way of thinking though, lead the person to be careless and make mistakes. Unfortunately, police can't run things up so if somebody can run an investigation from his own pocket and deliver them to the police, might have some better chances.
@eddie13: I strongly believe that you have to talk with a lawyer, tell the whole story and listen to his suggestions. Either way, your friend will have to file a lawsuit despite that she consent and gave the material or that she doesn't know the real perpetrator etc. At least you will know/ learn how things are (legally) and what paths your friend has available to choose from. To go illegally, well, is tricky. DW though is there...