WASHINGTON -- In the wake of the Columbine High School massacre, Sen. Orrin Hatch took on the makers of violent music and video games Tuesday.

The Utah Republican called for a federal probe into how the manufacturers are targeting youths. He also said he may push legislation to prevent youths from buying video games rated as appropriate only for older, "mature" players -- essentially making a current voluntary rating system mandatory and ordering stores to enforce it.Meanwhile, at a Senate Commerce Committee hearing where Hatch made the announcements, representatives of the movie and video game industries said their products are not to blame for violence such as the Littleton, Colo., shootings.

"Bold statements that claim as fact that video games cause violent behavior are, at best, overstated and, at worst, at odds with the prevailing academic literature," testified Douglas Lowenstein, president of the Interactive Digital Software Association.

Hatch isn't convinced, which is why he will seek next week to amend a juvenile justice bill to create a national investigation into how violent products are marketed to youths, and whether it contributes to violence.

He offered as an example of violent entertainment being marketed to children an advertisement for "Resident Evil 2," a video game rated for adults only featured in the magazine Sports Illustrated for Kids.

"Few people would argue that cigarettes, alcohol or X-rated or NC-17 rated movies should be advertised in children's magazines. Why should such violent video games?" he said, noting that the two youths who fatally shot 13 others before killing themselves in Littleton played violent video games obsessively.

Hatch also complained about slogans for some games. "The advertisement for the video game 'Destrega' states: 'Let the slaughter begin,' while the advertisement for the video game 'Carmageddon' states: 'As easy as killing babies with axes.' "

The committee invited makers of many violent entertainment movies and games -- Time-Warner, Seagrams/Universal, Sony, BMG, Viacom, Sega, Nintendo and Hasbro -- to speak at Tuesday's hearing.

"They all refused," complained Sen. Sam Brownback, R-Kan., who chaired the hearing. "It is disappointing that multibillion-dollar communication companies have no one on staff willing to communicate with us on this important issue."

Some representatives of movie and video game industry trade associations did testify and said they have given parents the necessary tools to guide and keep children away from unsavory products, and their products alone do not cause violence.

Jack Valenti, president of the Motion Picture Association of America, said the best and only real defense against the influence from bad movies allowed in a free society comes from home, church and school.

"Mothers and fathers, ministers, rabbis, priests, principals and teachers must construct within the minds and hearts of children an impenetrable moral shield," he said.

Without it, he said, "No congressional law, no fiery rhetoric will ever salvage a child's conduct or locate a missing moral core. If we, as a nation, don't understand that, we are lost."

But William Bennett, former education secretary who wrote the "Book of Values," said makers of violent movies, music and video games should realize they are harming society and should take some responsibility to change that.

"Almost no one, except for a few blinded by financial stakes, thinks that the popular culture is not having a coarsening effect on our kids. The evidence, empirical and anecdotal, is overwhelming," he said.

Bennett encouraged the Senate to subpoena heads of entertainment companies that did not attend Tuesday's hearing and ask them under oath questions such as, "Was the scene showing human brains splattered on the car seat a necessary part of your artistic statement? What was the point of including lyrics about child murder and molestation?"