I'm sure your mind is racing...
Have you thought about where she was... recounting events and people she was exposed to over the past couple of days?
On the innocent side of things: If she's a really active child who rides bikes, swings from monkey bars, etc. and is resiliant while she plays, she may have gotten injured, but then went on playing. She might not remember exactly what she fell on or how she hurt herself. Some kids just get so wrapped up with playing, running, and socializing that they can get hurt and move right on.... feeling the irriation of getting hurt but not wanting to stop playing.
Otherwise, I don't know what your boundaries are as a parent, but I can actually recount every male my daughter has been exposed to without my supervision. She's 16 now. From playing at the neighbors house, to transitions after school, to sports, I was there. I wasn't loose with her time at all so, if anything were to happen with her, I would easily be able to pin point exactly the time, place, and with whom. Our life was quiet, boring, and even anti-social at times, just to maintain a household free of a lot of traffic, people, and chaos. Structure was really important.
So, if your mind is racing because you can't narrow things down and pin point whom she's been in contact with, it may be time to re-evaluate your lifestyle.
In order to keep my lifestyle simple, very simple, I actually had to make decisions to not work and just be poor, quit school and just focus on the family. That meant not so many trips to McDonalds or even going out the movies.... we lived cheap and did activities that were free. The family complained about it, especially my daughter, but I'd rather myself be right there to pick her up from school, and volunteer in the school, and be involved in -EVERYTHING- than for even 5 minutes of inappropriate actions be done to her.
Maybe, neurotic. May be not.
All I can say is that now, she'd tell you, that "IT" never happened to her. And that I am very annoying.
I'm not trying to blame you as a parent at all, if someone has violated her. When something like that happens, the only person responsible for it is the person who did it. However as a parent myself, I can only tell you that I've made decisions based on the belief that not everyone is going to have the best intentions for my child. I am actually so protective that I was married to my husband for 7 years till I asked him to take care of my daughter alone. She was 9 by then, and it was only to drive her to school one morning. I never even asked him to watch after her while I took a shower or any simple situation that might arise when living together. And we met when she was two. I just felt that it was not his job to raise her or be her babysitter. It was only his job to be my husband, and support me so that - I - could give MY best to her. And he agreed with my boundaries. Anyway, I only shared that to show you the extent of protection it took for me to keep her safe from preditors, groomers, and any doubt in MY MIND about who she was exposed to.
Well, I hope that I only helped you to narrow down your thoughts....