It's been over 40 years since Jeffrey MacDonald was convicted of killing his wife and daughters. But he still claims he is innocent.

Family annihilation—wherein men kill their wives and kids (and, more often than not, themselves)—is so grotesque that it feels like it should only happen when a person is blinded by anger. But Chris Watts didn't murder his family in a fit of rage. We explore how his case breaks the family annihilator pattern.