TORONTO - When Toronto-raised filmmaker Larysa Kondracki was co-writing her debut movie "The Whistleblower," she had a lot of cinematic classics in her head.

She was thinking of Sidney Lumet's corrupt cop flick "Serpico," the Alan Pakula political thriller "All the President's Men" and Mike Nichols' acclaimed drama "Silkwood."

"What (those films) all did so well was they really put a character front and centre, and so, as much as you're unravelling a big mystery, you are going through it through a person ... who's learning at the same time at the audience," Kondracki, 34, said in a recent telephone interview.

"That's what makes something not so much about a subject matter but about the person going through it. And that's where you get your paranoia ... and your twists and turns because you're literally seeing the exact same amount of information as your main character is."

"The Whistleblower," opening Friday in Toronto, Vancouver and Montreal, stars Rachel Weisz as Kathy Bolkovac, the real-life Nebraska cop who took a U.N.-contracted peacekeeping job in Bosnia only to discover local officials were turning a blind eye to forced prostitution.

The film is harrowing, brutal and at times difficult to watch as Bolkovac realizes the enormity of the situation and tries to gather evidence and convince victims -- including two Ukrainian girls -- to come identify their tormentors.

Kondracki, who has Ukrainian roots, began reading about sex trafficking in 2003 and wrote a script about the subject with Columbia University classmate Eilis Kirwan.

The project came into focus when they learned the story of Bolkovac -- who was ultimately fired but sued for wrongful dismissal and went on to pen a book about her ordeal.

Emails to the former police investigator followed as did a fundraising call to Ukrainian organizations in Toronto, which raised $30,000 so that Kondracki could go on a fact-finding mission to Eastern Europe in July 2004.

That Ukrainian community, said Kondracki, is now celebrating the film's release -- she's heard that one person even went so far as to have "The Whistleblower" poster rendered onto a cake.

"I think everyone feels a little bit of ownership of the film and they very well should," she said. "It was a community effort. ... They're so proud."

"The Whistleblower," of course, is buoyed by some high-wattage star power.

Weisz is joined onscreen by Academy Award winner Vanessa Redgrave, who plays the head of the United Nations Human Rights Commission and Oscar-nominated David Strathairn ("Good Night, and Good Luck") as one of Bolkovac's few allies.

Kondracki says Weisz was always her first choice to play Bolkovac but the actress, who won an Oscar in 2006 for "The Constant Gardener," was pregnant when the role first came up.

"The Whistleblower" script ultimately languished at various studios and by the time they were ready to shoot, Weisz and the rest of the cast fell into place, recalled the director.

"I was in Romania in pre-production and these calls just started coming in going: 'What about Vanessa Redgrave?' and you're saying 'Sure, why not?' (and) 'What about David Strathairn?' 'OK!"'

Last September at the Toronto International Film Festival, Weisz said she wanted to play Bolkovac because it felt like "an important story to be told."

"I'm really interested in ordinary women who do extraordinary things, I guess unsung heroines," she said. "You know, Kathy did this extraordinary thing and I'd never heard of her and I think not many people had."

"I wanted the best actor possible and I thought she was it," Kondracki said on landing Weisz.

"(She's) similar to a Meryl Streep, or you look at Al Pacino or Dustin Hoffman in 'All the President's Men.' I think Rachel's the type of actress that blends into a movie instead of overshadows ... I think Rachel considers herself an actor first and sort of a star second."

When discussing her inspiration for "The Whistleblower," Kondracki speaks again and again of her admiration for "Silkwood," the 1983 film in which Streep plays a plutonium plant worker investigating alleged wrongdoing at her workplace.

"It was just a very similar story about a complicated woman who was a little bit out of her depth but who learned how to mine that field," said Kondracki.

"And also did some really, really risky things."