Associated Press
A police cruiser sits in the driveway and crime scene tape surrounds the home of Nancy Lanza in Newtown, Conn.

News outlets have gone to great lengths to catalogue the disturbing contents of Adam Lanza's bedroom. The accused perpetrator of the Newtown massacre had a cache of violent collectibles that included a plethora of guns and ammunition, along with nearly a dozen knives and three samurai swords, among other things.

The media focus has been almost exclusively on these externalities, with very little effort made to take an internal inventory of the thought processes that drove this man barely out of his teens to commit one of the most atrocious mass murders in American history.

There are, however, a few clues to his state of mind. The New York Times reported that he had several photographs of "what appeared to be a corpse smeared in blood and covered in plastic." It also noted that he had recently "cocooned himself in front of electronic game consoles in the basement of their home, playing warfare games." It's entirely logical to connect these violent images with his violent actions. Yet still, opinion leaders ignore this obvious correlation and focus more on the things he had in his possession rather than the reason why he had them.

A case in point is comedian Jim Carrey, who released an Internet video vulgarly accusing all legal gun owners of complicity in the Newtown massacre. In a follow-up op-ed at the Huffington Post, he announced that he "disagree[s] wholeheartedly with those who say… that more gun laws won't make a difference." He then added, "Change must start someplace."

We certainly agree with the need for change, but not with Carrey's starting place.

Carrey himself has appeared in a number of films where guns figure prominently as glamorous accessories or punch lines to a joke. His next movie, an R-rated action-comedy with a title too vulgar to print in a family newspaper, features Carrey as "Colonel Stars and Stripes," a masked vigilante who repeatedly pummels people with a baseball bat. The red-band trailer includes a scene where the hero murders a man with a rocket launcher, and the last shot is Carrey aiming a handgun at another man's face.

Lanza's collection is unsettling because someone who stockpiles violent paraphernalia already had an unhealthy obsession that likely began long before the collection did. Violent movies and video games are deliberately designed to feed those obsessions.

If Hollywood celebrities are looking for a place to start, why not begin with their own films?