Any possible prosecution must start with the police report. Until that happens, nothing else will either.
Mom and dad might also want to do some serious intervention and break these two up. A minor under 16 who is already hanging out with an 18 year old BF and smoking and experiencing sexually-related assaults needs to be a protected from her choices too - and they need to be jumping on this sooner rather than later. That might mean taking her phone, limiting computer access, even getting a restraining order against Mr. Wonderful. It's a very short jump from where she is right now to being pregnant or otherwise drug adicted or worse.

