Opinion in the absence of information is a specialty of our times. So when Adam Lanza committed that most inexplicable of crimes, opening fire in Sandy Hook Elementary school last year murdering twenty children and six adults (and, ultimately, killing himself), the explainers instantly began to tell us why. The 20-year-old Lanza, who had easy access to an arsenal in his own house, was mentally ill, a loner, a video-game freak. He was, moreover, a child of divorce, traumatized by his parents’ split. He was homeschooled. His mother, a gun nut and survivalist, enabled his madness, promoting shooting as family fun. I read these theories and dismissed them out of hand: These were stock complaints from both sides of the culture war using this horrific event to bolster their side.

This urge to reason away, I have long believed, results from a human impulse to disassociate from evil, to make it “their” problem, not “ours,” and thus protect ourselves and our children from the knowledge that sudden, random harm can occur at any time. We are the “good” parents, not the bad ones. We play “approved” video games, not unapproved ones. We would never.

But the terrible truth is that we don’t know why Lanza killed those kids. (Though the how is a different story: Lanza’s spree — he slaughtered 26 people in fewer than eleven minutes — would have been impossible had he not had a wide selection of semi-automatic weapons within his reach.) People do horrible things and they always will, and pointing fingers at the coarsening of culture and that poor, murdered mother — he shot her in her bed before he drove to the school — only deflects us from our grief and horror. Bad, deluded, or neglectful parents are a dime a dozen, but their kids rarely grow up with an ambition to shoot schoolchildren. Half of Americans are divorced, yet most of their offspring live healthy, productive lives. Contrary to the London Telegraph’s reporting early on, autism (and its cousin, Asperger’s) is not a predictor for violence or criminal behavior, as the Columbia Journalism Review pointed out, and though violent video games may not be your thing, millions of young men play them – 80 percent of high-school boys, according to the New York Times — mostly without serious side effects. “It is not at all clear whether, over longer periods, such a habit increases the likelihood that a person will commit a violent crime, like murder, rape, or assault, much less a Newtown-like massacre,” the Times concluded.

And then I read the State’s Attorney’s report, released this week, and found myself at odds with myself. So many of the details therein point, if obscurely, to the causes the opinion-makers first proposed. Nancy Lanza may have been a doting mother, buying him a car and a new computer, and leaving him his favorite foods while she left town for several days; and she was attentive enough to tell friends that she was worried about her son. But somehow she did not see the extent to which her child was eluding her grasp, how the quirky boy became a dangerous young man who could not tolerate strangers in the house, who would communicate with his mother only by e-mail, who taped garbage bags to the windows of his bedroom, and would not allow her to enter. “She was not allowed in the shooter’s room, however, even to clean,” the report says. “No one was allowed in his room.” Nancy Lanza was so blind to her son’s violent yearnings that she wrote him a check — discovered when the police searched her house — to buy a new pistol for Christmas, a CZ 83. This raises the fear that lurks in the heart of so many parents: Is it possible to raise a monster and never have a clue? Or, having a clue, are the parents complicit in his sickness? Were Nancy Lanza and her ex-husband Peter, who lived less than 50 miles away, enablers?

The list of video games that Lanza liked to play reads like an orgy of snuff porn. Left for Dead. Dead Rising. Half Life. Battlefield. Call of Duty. Dynasty Warriors. Team Fortress. Most hair-raising: a computer game called “School Shooting,” in which “the player controls a character who enters a school and shoots at students,” according to the report. These games likely did not create Lanza’s taste for murder, but very possibly they abetted it. The games “are like porn to a rapist,” a law-enforcement officer told Mike Lupica of the Daily News in May. “They feed on it until they go out and say, enough of the video screen. Now I’m actually going to be a hunter.” As a journalist and a citizen I will defend most freedom of expression, even if that expression is violent. As a parent, the list gives me chills.