20/20: Crespi Murders/Contract on Mom/House of Yahweh

A dark secret of a father's bouts of depression turned deadly when he murdered his twin daughters. His wife made headlines when she forgave him and stood by his side. Then, the report of a teenage girl caught on tape plotting to murder her mother. Finally, a look at a religious sect called the House of Yahweh who some people believe is really a sex cult run by a bigamist.