For the past year, UC Berkeley Graduate School of Journalism students Ellie Lightfoot and Kathryn Hurd have been investigating the background of Steven Carrillo, an alleged murderer with connections to alt-right extremist groups in the “Boogaloo” movement, as part of their work with the campus Investigative Reporting Program, or IRP.

Before long, the story surpassed initial expectations. What started as a small investigation quickly became a yearlong process and collaboration with the Public Broadcasting Service series “Frontline” and ProPublica. The project culminated in “American Insurrection,” a 90-minute documentary premiering Tuesday that investigated the dangers posed by militia groups, white supremacists and other extremist organizations, according to a press release by the Graduate School of Journalism.

Geeta Anand, dean of the Graduate School of Journalism and Pulitzer Prize-winning journalist, said the collaboration with “Frontline” and ProPublica emerged unexpectedly. She and David Barstow, head of investigative reporting at the Graduate School of Journalism, had been discussing a campus-related partnership with “Frontline” when further conversation revealed that they had been working on the same story and could benefit from working together.

“The story is important because it shows how someone can become an extremist and how pervasive the extremist ideology has become in our military,” Anand said. “It also served as a great opportunity for the journalism school and the IRP because it is the first of what we hope will be many collaborations with ‘Frontline.’”

According to Lightfoot, the experience of working on the story was both grueling and “extremely rewarding.”

Lightfoot began the investigation last summer with Hurd and Gisela Pérez de Acha, a Graduate Schoolf of Journalism alumna, by looking into the history of Carrillo, the ex-air force sergeant who was charged with the murder of two law enforcement officers as part of the “Boogaloo” movement, an alt-right extremist development. As part of their investigative journalism, they reached out to Carrillo’s friends and family, looking for more background on his involvement with the extremist group.

“We wanted to give a nuanced and detailed account of how he became affiliated with the ‘Boogaloo’ movement,” Lightfoot said. “It was a capital insurrection, and it was difficult to find a time to publish this story. This collaboration with ‘Frontline’ came at the perfect time.”

Hurd echoed Lightfoot’s sentiment, reflecting on how difficult it was to report on a story such as the one they had been working one.

According to Hurd, she was grateful for the guidance offered by Barstow, who served as the editor for the story. Despite the hardship, Hurd said she thought it was a “privilege” to be able to work on the investigative piece for so long.

“What I’ve learned from doing this work is that to produce any substantial, accurate and good piece of investigative journalism, you have to be prepared for bumps in the road,” Hurd said. “You have to be patient and understand that there’s a lot of things that are beyond your control.”