Given that neither of us have seen the evidence, I am comfortable accepting the coroner's conclusion. As I said, the coroner is the least likely to have a stake in the story.
I knew three kids who were being sexually abused when I was a child. One by a step-father, one by a step-brother, and one by an uncle.
It does happen that elementary school-aged children commit suicide. It is, thankfully, rare, but it does happen.
The police aren't accepting it, and they are going forward with an investigation:
From the article:
Evanston police Cmdr. Tom Guenther said the coroner's finding of suicide would not affect how police conduct the investigation. Asked if the finding ruled out any possibility of foul play or an accident, Guenther said, "I don't think we're going to jump to any conclusions at this point."