After years of work, St. Paul writer Vince Flynn's no-holds-barred hero Mitch Rapp is finally making the big screen.

This weekend sees the national release of "American Assassin," which tells Rapp's origin story. Flynn died in 2013, so for his family, the film's release is particularly emotional.

Having lost someone he loves to terrorist violence, Rapp is a man looking for vengeance. He trains himself to be an unstoppable secret warrior, adept at combat, at ease with tracking and entrapping foes through the internet, and as well versed in Arabic as in English.

He starts out on his own but ends up working for Orion, a CIA unit deep undercover. It's there he meets Stan Hurley, a senior officer who believes Rapp is undisciplined.

"What is it you think we do here, Rapp?" Hurley asks.

"I think we kill people who need to be killed," Rapp replies.

"Who do you trust to tell you?" Hurley demands.

"Follow orders," Rapp grunts back.

"No, you follow orders when they suit you," snarls Hurley. "This whole thing is pretty much a means to an end for you, isn't it?" Actor Dylan O'Brien, who plays Rapp, said his character "wants to completely bludgeon the guys who did it to him."

"He's got so much anger inside of him, he's got so much pain inside of him, but he's also a very smart and capable and athletic asset, in a way," O'Brien continued. "He really trains himself, he really drives himself to be this weapon."

Vince Flynn in 2005, posing with his books. Jim Mone | AP file

O'Brien was in the Twin Cities last weekend for a special Minnesota premiere of "American Assassin."

The film is a nonstop action thriller. While it's a story about trying to prevent international terrorism, there is very little politics. This is good versus evil, and it gets bloody. In an interview with MPR in 2000, Vince Flynn said that while Rapp is an assassin, he isn't indiscriminate.

"It's the old argument, one man's terrorist is another man's freedom fighter," he said. "Now you hear that line bantered around all the time, and I kind of agree with it. But where I disagree with it is when innocent women and children are attacked."

Flynn's widow Lysa says in many ways her husband was Mitch Rapp.

"Mitch's dialogue, a lot of that was just how Vince would speak," she remembered. "I know they thought the same, had the same fierce passion for what's fair and what's right. So I guess I could say I did live with Mitch Rapp for a few years."

Lysa Flynn said work began on adapting Vince's fiction for the screen 10 years ago, while he was still alive. As can happen with movies, it took a long time for everything to fall in place. She joked that when the effort began, Dylan O'Brien was only 15, so they had to wait for him.

O'Brien became a star as a teenager, first on the "Teen Wolf" TV series, then as Thomas, the central character in the "Maze Runner" movies. It was during the making of the third film in that series, "The Death Cure," that O'Brien was badly injured when a stunt went wrong.

The production was postponed indefinitely. It was while he was recovering that he was offered the Mitch Rapp role.

"Yeah, you know, it was interesting how timely this was for me in my life," O'Brien said.

As he struggled through a long recovery from his injuries, he felt an affinity for Rapp and his situation.

"I was spending so much time with this script and this story, and what I wanted to do with this character in my head, that I felt the most mentally prepared for something," O'Brien said. He has since finished "The Death Cure."

Having O'Brien as Mitch Rapp is already paying dividends. Lysa Flynn said the actor was swarmed by young female fans on location.

"Just to see his shadow go by, they would lose it," she said. "And so because of Dylan signing on to play Mitch Rapp, all of a sudden there's a whole new group of people reading the books."

And because there are so many of the books, everyone involved in the production, and especially O'Brien, hopes this may become a movie series.

"Yeah, I'll be about 75 at the end of it," he laughed. "Using my walker to hit guys."

Lysa Flynn said as the film is released it feels good.

"That's the emotional part about seeing this all come to life now," she said. "It's like having Vince back with us, in a way."

Lysa Flynn said she loves the film, and she knows Vince would have loved it too.