Evil Thoughts, Wicked Deeds and 20 Years of Workplace Shootings are two of the sessions that take place during the annual conference of the Association of Threat Assessment Professionals (oddly held at Disneyland), where hundreds of psychologists and law enforcement officials race to stop the next mass killer. “Mass murder is not an impulsive crime — and therein lies the promise of threat assessment.”

+ The NYT looks back at fourteen recent mass shootings with a single question in mind: How did they get their guns?