[Napalm]

Criminalistics suggest that this is an emergent behavior directly correlated to the way the males in their lives behaved around them. With each successive generation, the behavior gets worse. But its only emerges when they acquire a mate, because that is where they saw the behavior directed. So they begin to do the same things they saw, until it eventually surpasses what they saw their fathers, uncles, grandfathers..., doing. When the spouse begins to show signs of independence from the abuser, the abusers behavior is exaggerated, and it starts a cycle that eventually goes from subtle comments to horrible physical and/or sexual abuse to even rape and murder. Its pretty textbook with Mark Hacking, but with Scott Peterson, its not as clear, his seems to be more erratic, but still present.