Denver ? Some parents of children killed in the Columbine massacre praised a new documentary about the killings, saying it contributes to the fight for tighter gun control. Others said the film exploited tragedy.

“Bowling for Columbine,” shown Saturday at the Starz Denver International Film Festival, uses the slayings as a launching point to examine violence and gun culture in America.

“It was difficult at times to watch,” said Tom Mauser, who has campaigned for stronger gun laws since his son Daniel was killed in the 1999 school attack.

“I realize that some will say, ‘Maybe these films shouldn’t be shown.’ I say no. To not take on the subject of gun violence is to ignore it, and we’ve done that for too long,” he said during a panel discussion.

Not all Columbine parents agreed.

“I doubt there’s much of a redeeming quality to that movie,” Brian Rohrbough said Friday. “This is just a guy trying to capitalize on the tragedy of others.” Rohrbough, whose son, also named Daniel, was among the dead, had not seen the film.

John Tomlin, whose son John died at Columbine, said he has not paid much attention to the movie.

“I’m not that interested in finding out,” Tomlin said.

The film is by Michael Moore, the left-wing author and documentary maker known for his film about GM, “Roger & Me,” and his best-selling book “Stupid White Men.” It examines other tragedies like the Oklahoma City bombing and at U.S. government policy overseas to probe the roots of violence in American society.

“The film has actually very little to do with Columbine and a lot to do with how we have behaved in what is otherwise a very good society,” Moore said.

Jefferson County school officials said they were apprehensive about the movie’s release and want to see it to gauge its emotional impact.

“It’s something that may draw students and family members, so it’s something we want to view and need time to prepare for,” said school district spokesman Rick Kaufman.

The film’s distributor United Artists has scheduled two advance screenings Tuesday and Wednesday and will ask school district officials to attend.