i'm not convinced that she didn't sneak out with friends, kids do that all the time, and their parents don't know. I would be interested in who she was chatting with online, maybe, and just a maybe some of them decided to sneak out and just hang out together for awhile down by the water, everybody bring a blanket or something to sit on, and then maybe something happened, an accident...kids panic, don't want to get in trouble for being out...so they wrap her in a blanket and put her in the water...i'm not saying thats what happened but it is a possibility, wouldn't make her a bad girl or anything, just normal kid stuff...
i'm just not convinced that someone in her family did something to her.
jmo