You know mental illness does not just happen. This woman was showing signs of flipping out long before she did this. People around her were seeing signs that she was “loosing it” but more than likely did not know what to do or how to handle it. Or maybe, just did not care, it’s hard to say really because we don’t know who was around her. I know for a fact though that before this happened people saw a change in her but did not know what they were seeing.
And if they ever interview the friends/ family members they will say: “Well we knew she had problems but....” or my favorite: “I just knew she was a bad’un.”