In the new drama Imperium (out in theaters and on demand Aug. 19), the very busy Daniel Radcliffe plays an FBI agent who goes undercover to infiltrate a group of white supremacists building a dirty bomb.

“It was inspired by real events and co-written by Michael German, a former agent who spent years inside the neo-Nazi movement,” says the film’s director Daniel Ragussis. “Daniel Radcliffe plays Nate Foster, the agent. His greatest strengths are his intelligence and his people skills; I learned from Michael that actual undercover agents are primarily master manipulators — able to win confidences, control situations, and out-think the enemy, even when mortal danger is staring them in the face. Toni Collette plays Angela Zamparo, his case agent and supervisor. She’s spent years focusing on white supremacist terrorism and is really the only person out there that’s focused on keeping Nate alive.”

The director says — worryingly — that the more he learned about the topic, the more timely and relevant it seemed. “We’re witnessing a surge in far-right groups all across Europe; in some cases they’re nearly winning national elections,” says Ragussis. “We have a stereotype of what it means to be a white supremacist, but when I began collaborating with Michael and doing my own research, I was stunned by the depth and the extent of this movement.”

Ragussis made every effort to authentically portray the experience of going undercover, as well as the modern-day white supremacist community. “There’s a large white supremacist rally in the middle of the film that we had spent months researching and planning,” the filmmaker explains. “There were so many details that had to be captured to try to make it real and authentic. I’d read about them, seen them, watched videos of them — but to actually see it come to life by our own hands was something I’ll never forget. Someone even called the news and erroneously reported a Klan rally in their neighborhood! So to that extent, I suppose we did our job.”