Minutes after Robin Westman opened fire on a Catholic school mass packed with children, the shooter's shocking manifestos spread across internet. Videos posted to YouTube and notebooks scrawled with musings as unhinged as they were hateful provided uncommonly deep insight to the mass killer's mind. Westman, 23, appeared to be obsessively planning the massacre at Annunciation Catholic School and Church in Minneapolis for months. The killer opened fire through the building's stained-glass windows on Wednesday morning, killing two young children and wounding 18 others. The deranged murderer took her own life at the end of the shooting, leaving only a...