Steve Kazmierczak, the Northern Illinois University graduate student who opened fire in a lecture hall this week, killing five students and wounding many more before killing himself, was not the archetypal brooding loner. Reportedly he “was revered by the faculty and staff and students alike,” “nice,” “engaging,” “motivated” and “responsible.” He purchased and registered the murder weapons, a 12-gauge shotgun and 9-millimeter pistol, legally from a gun dealer. He had recently stopped taking medication for an as-yet unreported condition and had shown some erratic behavior, but nothing that raised alarms. He left no note and there is no reported connection between Kazmierczak and the students he killed. We like to think that there is always something that could have been done, but that’s not so here. On the continuum of senseless killings, these murders are at the extreme.