I really liked this. The ambiguity is frustrating in a fun way, wanting to know exactly what happened. I particularly liked the opening paragraphs, never having been one to enjoy sitting through church of any kind.

ohh! me likey...me likey a lot...though I do wonder what mind it is that creates such a dark story (kidding...dark stories are fun!)

Split personality? Just my own interpretation, which I could make because you left it so deliciously ambiguous at the end... one of the final lines, "smiling darkly", gave me the awful feeling that Billie was not entirely blameless when it came to the family tragedy. That may be way off, or dead on, I dont know, but one sign of a good story is that it stays in your mind for a long time after you have read it, retelling itself so that each time you think of a character, you realise something new.