Troy Duffy director of “The Boondock Saints II: All Saints Day,” says the film was much harder to do than its predecessor because it was “a much more complex script.”

BOSTON — Although the vigilante film “The Boondock Saints” was released in 1999 for a limited run of only two weeks in just six theaters, producer Chris Brinker says that the film, which many people have never heard of, has “conservatively” grossed more than $60 million in home video sales and “is passing $100 million worldwide.”

That’s why Brinker has again teamed with director Troy Duffy and most of the original cast for “The Boondock Saints II: All Saints Day,” hoping they can do in theaters what the first film failed to do a decade ago. Back when they were shopping the film to studios in the late ’90s, says Duffy, the Columbine High School shootings occurred. Suddenly no one was interested in a violent film, even one that revolved around a pair of brothers who shot up mobsters rather than a high school.

So the filmmakers pooled their assets and rolled out “Boondock Saints” to only five theaters, including two in Los Angeles and one in Waltham, Mass. Although business was very brisk and even got better through word of mouth, Brinker says they only had a two-week window to show the film theatrically because it had already been sold to the USA cable TV network.

But then they made a deal with Blockbuster Video, which at the time was a major force in home video rentals. Brinker says that before long Blockbuster had put 60 copies of the film in each of its 6,000 stores and placed big posters for it in store windows promoting it. In short order, again thanks to word of mouth, Brinker says you’d be hard pressed to find any of the 60 copies in any Blockbuster store. They were flying off the shelves as rentals.

That’s why Duffy and Brinker, who are sitting in an upstairs lounge at the Irish pub The Black Rose not far from Faneuil Hall, are more confident this time around, backed by a strong fan base. The film has its own Web site and there are many fan sites as well.

“The Boondock Saints” has become such a cult film, especially among the 18-to-34 age group according to Duffy, that “There are people who just know every single frame and every word of the film. I’m constantly amazed at how many fans are out there. Every kid who watched it became another drooling ‘Boondocks’ fan. Entire families have watched it.” Then he adds with a chuckle, “Families that drink a lot.”

Brinker says the film continues to win new converts. “Some people found it in 2000. Some found it last week.”

“It’s a hand-me-down film,” adds Duffy.

The original film was a mixture of the then-very-hot violent films from Hong Kong, blue-collar Boston toughness and a strange view of Catholicism that apparently touched a nerve in a lot of people. In the film, a pair of Irish brothers — Connor and Murphy MacManus — accidentally kill members of the Russian Mafia in Boston who are trying to take over their favorite pub. Because of this deed, they become local heroes. Hearing a voice from God, they begin knocking off Mafia gang members one by one, feeling they are doing God’s will in ridding the world of evil. They have the secret support of the cops who are trailing them as well as of members of the Catholic clergy. Risking their lives for their beliefs of Veritas (truth) and Aequitas (justice), the Boondock Saints become saints. Yet at the start of “Saints II,” they are hiding out on a sheep farm in Ireland with their long-lost father, a former assassin . . . until the murder of a beloved priest in Boston draws them back to the city and back to the mayhem.

Although the budget jumped from $6 million for the original to $8 million for the sequel, there’s a 10-year inflation rate to contend with. And although there were three extra days this time around to shoot it in Toronto, for a grand total of 35, Duffy says it was much harder to do because it was “a much more complex script.” Although he says he began writing the sequel “the day I stopped writing Part I,” it was “more difficult because it was like I had to crack the right code for the script.” He knew that he wanted to “throw a curve ball” in the new script to give the movie’s fan base some surprises. “One of the things about why the most successful sequels worked was because not only did they give you more bang for the buck, but they would throw a curve ball to the audience.” He adds, however, that once he figured out how to do that with the new script, “I completed it in 30 days.”

Although Brinker and Duffy, who has “Veritas” tattooed on his left forearm and “Aequitas” on his right, are certain their fans will support “Boondock Saints II,” they’re opening it in only the six cities where they feel the movie’s fan base is strongest — Providence, Boston, Philadelphia, New York, Los Angeles and Hartford. If it does well in those cities, promises Brinker, it will roll out to other cities. If not, well, there is always video.

mjanuson@projo.com