Investigators are analyzing a notebook believed to be written by James Holmes, the accused gunman in Friday's Colorado movie theater shooting, which could be a roadmap to a massacre.
If it is, it would not be the first of its kind. Experts say detailed, meticulously written plans are often a hallmark of mass murderers.
"Universally, mass shooters [are] all about revenge," said Brad Garrett, a former FBI special agent and an ABC News analyst. "He wanted to pay society back for what he believed...Full Story