Disclaimer: Personal opinion only, no legal experience.

Personally, I remember how incredibly dumb I was when I was 13. I am very glad I grew up before technology like this became common, otherwise there is a good chance I could have performed an equally stupid move. I have sympathy for this young fool. Here's what I would do:

• 1) Talk to the parents first. Hopefully they are sympathetic and thankful you did not go directly to the police.

• 2) Debate with his parents as what should be done. Odds are his parents would prefer to handle this by themselves, with no school or police interference.

• 3) I would suggest writing a formal letter of agreement about actions that need to or, as importantly, need to not be taken. Be specific with the following:

  • Punishments to be had. Does he need to volunteer somewhere and/or get grounded?
  • Agreement that nothing like this should ever happen again or more drastic actions will be taken. Should something like this happen again, mention that you'll go straight to the principal or police. Be specific with what constitutes unwarranted sexual advances; a nude photo is obvious, but text messages could be considered more of a gray area.

• 4) Have everyone sign the agreement; legal guardians and children.

This likely won't qualify as the strictest of legal documents... but should another incident happen this is a signed piece of proof that shows a history of this type of behavior. I want to believe that the boy is not malicious in intent, but instead just a typical dumb teenager who literally did not know better... so I think this will be enough to smack some sense into him.