It seems that the pieces are slowly emerging to form a fairly coherent explanation.
Perhaps sadly, this doesn't surprise me. A few of us were suggesting this days ago, but kept getting deleted. Sadly I and perhaps a few others here have seen true evil and know what people can do.
A few here seem to be struggling with what we are learning, and are determined to stick with inexplicable "explanations"
Incidentally, you can be sure the authorities are monitoring this thread. There is always a long shot someone here might come up with something from left field they haven't though of. Also if there were any co-conspirators, there is a fair chance they will be watching. Plenty of arsonists are apprehended watching the fire. I don't believe there are any co-conspirators and belief this was a lone wolf. But you never know.