In America, this week's carnage at Columbine High School in Colorado, the worst school shooting in modern times, has renewed charges that media violence, propagated by Hollywood, is to blame.

Lethal teen violence has extraordinarily complex roots, but clearly access to weapons, and a sense of alienation, were factors in this killing spree.

So was pop culture - at least that's the view of a widening circle of psychologists, and religious and political leaders.

Keanu Reeves stars in violent new movie The Matrix

The two suspects in the Colorado slaying, Eric Harris and Dylan Klebold, favoured the all black attire seen in the violent new movie The Matrix, and they were drawn to the nihilistic Goth music exemplified by shock-rocker Marilyn Manson. Harris also maintained a Web site which depicted him as a fan of computer games like Doom in which players kill their opponents with high powered "virtual" weaponry.

Sabrina Steger, whose daughter was gunned down by a fellow teen in a high school shooting in Kentucky sixteen months ago, firmly believes that pop culture can trigger teen violence. Although she's at a loss to explain exactly what motivated the killings in Colorado, she told me she has no doubt that children today have become "desensitized" by the influence of media and video games.

Mrs. Steger, along with the parents of two other children who were slain in the same incident of teen killing, is taking Hollywood to task. This month, collectively, the parents have filed a lawsuit in which they are seeking $130m from 25 entertainment companies, including media giants Sony and Time-Warner.

Their contention is that Michael Carneal, the teenager who gunned down their daughters, was inspired by media violence when he fired the lethal shots.

Computer games like Doom have come under new fire

Specifically, the lawsuit claims that Carneal was influenced by violent computer games, including Doom, pornographic websites and the 1995 movie The Basketball Diaries, in which Leonardo DiCaprio portrays a character who who dreams he guns down a teacher and several pupils.

Jack Thompson, the lawyer representing the parents, likens the lawsuit to a product-liability claim. To him the Hollywood entertainment companies who create games, movies and websites are no different from car manufacturers.

In his line of thinking if a video game or a movie leads to a death, then the company that produced it created a defective product and must, therefore, pay out any damages, just as they would in a product-liability case.

Experts argue that similar lawsuits have failed in the past because of the legal precedent that a media company must actually be seen to incite violence to be liable for damages.

DiCaprio starred in accused film The Basketball Diaries

Past experience shows it may be very difficult to prove "incitement" or that any of the defendants intended their entertainment products to be harmful. Also, courts have previously thrown out suits that try to hold record companies, or movie producers, liable for their products on the grounds that they are unconstitutional and infringe on cherished First Amendment rights to free expression.

Jack Thompson maintains his aim is to hurt Hollywood with the lawsuit in an effort to curtail media violence. He told me he wants those who run entertainment corporations to adhere to a golden rule that amounts to "don't do to other people's kids what you wouldn't do to your own." Politicians have been quick to exploit this theme.

The day after the Colorado school massacre Gary Bauer, the leader of the conservative Family Research Council, announced he was running as a Republican presidential candidate and declared "in the America I want, those Hollywood producers and directors, they wouldn't be able to show their faces in public, because you and every other American would point to them and say : Shame! Shame! Shame!"

Shock rockers Marilyn Manson are back in the spotlight

Clearly, many Americans are angry, and this lawsuit represents an effort to extract penalties from Hollywood for perceived transgressions.

Whether the suit succeeds or fails, it is focussing attention on the content of pop culture. It is also putting pressure on Hollywood companies to realise they can't hide behind the constitutional safeguard of the First Amendment.

Personally, I would be heartened if this lawsuit prompts filmmakers to accept that their right to freedom of expression, enshrined in the constitution, is not absolute.

The use of violence in any media product can have consequences, and those producers who use violence have to accept this responsibility.

But it is also clear that scapegoating Hollywood is simplistic and easy - it is no substitute for the much harder task of searching for the root causes of teen violence.