Of course there should have been an investigation. You can't just take someone's word for what happened, the very idea of doing that would be ridiculous even if the older sister had been positively saintly up till the incident, that doesn't mean she would never lie or anything.
Yeah, it seems very real. It is a true story, I could prove it. It will take me a while to find the newspaper, but I could link it when I find it. What I meant is I probably got some of the facts slightly over-stretched or whatever.
I'm being nitpicky. I'm sure it is based off your life, but also keep in mind, I know full well what a big difference something actually being your life, and something being based off it is, and that's really something you have to do yourself if you want peace, find a way to stop telling the "based" off story, and accept the real one as the truth.