To the poster who wrote this:
'Seriously, you're posting here. Where is your daughter now?' and to ANYONE else who has implied OP is or has behaved 'wrongly, I would very politely ask you to STFU. Unless you as a DM have been in that precise position, you will have no clue of the chaos and conflicting thoughts (IE 'I want to protect my DD/my DD doesn't want to report it', vs 'But I can't not do anything' etc etc ETC). Truly, trust me, unless you have been in those PRECISE shoes, do NOT comment on the OP but restrain your comments to the advice/guidance she is seeking at a time of shock and stress and trauma.
Mandatory Firstly, I am so so sorry that this has happened to your daughter; likewise for what you are now going through. It - ALL of it, the feelings, the knoweldge, the emotions, the tough choices - are things I would not wish on my worst enemy, but I do, unfortunately, know them only too well.
For what it's worth, here is my advice.
1: I'm not certain from your OP, but if she was forced to commit a sex act on him then please try and gather together the clothes (all of them) she was wearing at the time as they may have evidence on them;
2: You are ALREADY doing the singular most vital thing, which is both instantly believing your daughter and allowing the trust she has in you to ensure she is speaking freely to you.
3: It is is equally vital that she KNOWS she is being LISTENED to in HER choices; but it is equally (although sadly 'opposingly') vital that this IS reported to the Police and the sooner the better.
4: Would second those who have said ring Rape Crisis or similar for advice, but you'll need to have a conversation with her explaining that 1 in 3 females will suffer some kind of sexual abuse/attack; that she is NOT 'alone' (nor ANY of the other things that victims of SA crimes often feel); that even if she feels she cannot press charges* it IS vital that she at least speaks to police in order to protect his next victim (and there will be one; sexual predators only increase their behaviour, never 'decrease' it; and there is absolutely no way that this was some kind of normal teenager behaviour that 'got out of hand' or whatever it is he would say vis it).
5: Explain to her that you, as her Mum but also as an adult who HAS to be aware of other victims too (it may well be the latter BTW which enables her to feel differently regarding reporting it), have a duty to report it to the police both for her and that next victim; and that that is what you have to do, but you will do it in a way that as best possible meets what she FEELS right now as HER immediate needs/concerns (as those are borne from immediacy; shock; her worry re social circle etc, as ALL of those are 'normal' and 'valid' feelings right now but will likely change - ESP. the social circle one, as it is his shame not hers and the Police will ensure that THAT is reinforced to her in as gentle a way as possible.
6: As best as can, try and 'split' the two things. IE that it is YOU who is doing the 'reporting', but it is her who both needs that to happen for herself and for others. If she has a younger (10-12) relation or friend you can think of, one route is to ask her what she would want you to do if it was THAT person. Empathy is often the thing that can break down the natural wall of fears she has right now.
7: Explain to her the * above, which is that she CAN speak to the police now but will NOT be forced to press charges (but also please know yourself that she is MUCH more likely to be comfortable with the latter once she has been supported by the Sapphire police officers). Very lastly, explain to her that it is possible - even likely - that this creature ALREADY has some form; that the police may already be aware of him; that he may have already abused one or more other girls. That if that is the case, they may not have been able to secure a conviction yet, but that her speaking to them might well be the thing that changes that.
8: Empowering her as much as possible is vital right now, and then so is counselling etc., but you CAN find a way of making clear to her that the 'reporting' really IS your ONLY choice of action but whilst simaltaneously NOT inadvertantly exacerbating the internal feelings of powerlessness that follow an assault.
- I know a 10 year old who who was raped, and after the pretty classic MO of escalating offences and relying on the fear of 'telling' had worked. Help her understand that whilst you recognise her pain and fear, she has the power to act; power that will itself than help her long-term recovery from this, AND power to prevent him from escalating whilst shielded from Police attention.
I'm so so sorry for 'bullett' style of above, and if any typos or 'wrong' words but am typing at pace as I'm desperate for you to be able to retrieve her clothing if that is still possible, and likewise to offer as much guidance as can from what I know.
Sending you and DD loving hugs, and just the hugest of strength.