What the fuck. That is horrible. It's sad that these people can get so emotionaly ill as to do something like that
http://www.4woman.gov/faq/postpartum.htm It explains her type of depression. If you add this upon depression itself, without professional help actually there (like the article says, she stopped getting help and all because they thought she was cured), then something is bound to happen. She might have killer herself, but she probably took it out on the baby. I agree it is sick to hear this kind of stuff, but at the same time, it's not okay, but it's not surprising she did something like this, depression on it's own is already sometimes hard for people to take, so throw in some other elements and you have got one messed up situation like this.
it's sad that we always stop people with those kind of problems just when the worst is already done..