On a cool California evening in the exclusive ocean community of Palos Verdes Estates, a police cruiser pulled up to 2019 Via Visalia, a rambling ranch house nestled in the hillside. Inside, the police found a shattered pair of eyeglasses, a bloody pile of clothes, and the naked body of a middle-aged woman that showed signs of being raped and beaten. In the hours that followed, two astonishing facts would come to light: that the woman's husband was the personal attorney to President Ronald and First Lady Nancy Reagan. And that her younger son Michael was the prime suspect in her murder. The...