She was trapped inside an overwhelming delusion,...
Yep, she sure was, the delusion that the Supreme Ruler of the Universe existed in the first place, and that it cares what she does. All else followed from that delusion, but she had a sure enough mental lack as well, such as her low IQ. But she was able to care for the kids, apparently, so I don't know what to think about her ability to stand trial or to have known the wrongness of her crime. This is always a tragic thing, but it happens all too frequently. Sometimes I think the God delusion is just a convenient excuse, a means of getting off the hook. People have been killing unwanted children since before we were human, but the socail stigma, as well as the legal penalties of doing so these days is an obstacle that makes child-killers have to think of adaquate excuses, and religion is a mainstay for them.