I really don’t see why cops are so fascinated by the motives of mass-murderers — people who, by definition, connect thoughts and actions in ways that are beyond the pale. In theory, their motives can’t be generalized, so what exactly is gained from this exercise? Aside from the satisfaction, I guess, of reenacting some barnacled ritual, that is…
Actually (surprise!), I do see why they’re fascinated. It’s a way of deflecting from the plain facts of large-scale death. It creates a discursive space for all kinds of “mitigating” factors to creep it: like, “well, you didn’t really murder that person because you…” (pick one): (1) thought he had a weapon, (2) were standing your ground, (3) believed you were defending yourself, (4) felt threatened, (5) were cleaning / showing off your weapon. And that menagerie of factors, in turn, enables the arbitrary exercise of authority: they serve as special dispensations that cops can grant to some killers (themselves first and foremost) but deny to others. (🤔 I wonder who benefits…)
The bitter inequalities of the US — social, political, and most of all economic — are held up by a scaffold made, literally, of guns. If we got rid of them, it would be much, MUCH harder to maintain the reigns and fields of terror that keep people down. So, first and foremost, this fixation on murderers’ motives compensates for that poverty: it’s a magical space where delusions outweigh material facts.