Director Sebastian Junger, left, and producer James Brabuzon from the film "Which Way Is Front Line From Here" pose for a portrait during the 2013 Sundance Film Festival on Sunday, Jan. 20, 2013 in Park City, Utah. Director Sebastian Junger from the film "Which Way Is Front Line From Here" poses for a portrait during the 2013 Sundance Film Festival on Sunday, Jan. 20, 2013 in Park City, Utah. PARK CITY, Utah (AP) - Sebastian Junger wishes his latest Sundance Film Festival documentary never had to be made. It's been a bittersweet return for Junger at Sundance, where his war chronicle "Restrepo" won the top documentary prize three years ago. Junger's back with "Which Way Is the Front Line from Here? The Life and Time of Tim Hetherington," a portrait of his "Restrepo" co-director, who was killed covering fighting in Libya in April 2011. The film debuts April 18 on HBO. Junger and producer James Brabazon, a long-time colleague with whom Hetherington covered combat in Liberia, were glad to share the film with Sundance audiences but uneasy coming to a festival that's billed as a celebration of film. It's an odd feeling. James and I are maybe the only filmmakers in the town who are in some ways quite sad our film exists," Junger said in an interview alongside Brabazon. But it's also our opportunity to sort of communicate how extraordinary our good friend Tim Hetherington was. So I'm walking around, I'm seeing restaurants and street corners where Tim and I had conversations. I'm sort of flashing back. Yeah, it's a very kind of poignant experience. A portrait of a U.S. platoon in Afghanistan, "Restrepo" earned an Academy Award nomination for best documentary. Six weeks after attending the Oscars, Hetherington was killed by shrapnel from a mortar round. "Which Way Is the Front Line" chronicles Hetherington's early life in Great Britain, where he studied photography and first went overseas in 1999 to cover young soccer players in Liberia. In 2003, he returned there with veteran war photojournalist Brabazon to cover rebels trying to overthrow President Charles Taylor. In 2007, Junger, author of the best-seller "The Perfect Storm," enlisted Hetherington to shoot photos and video for "Restrepo." The two spent a year filming a platoon in one of Afghanistan's most dangerous war zones, capturing both the boredom of waiting around for the fighting and tragedy as U.S. soldiers lost close friends in combat. Hetherington was not the usual objective, fly-on-the-wall photojournalist. The new film reveals him as a chronicler of combat but also a humanitarian who engaged with his subjects and put his own life at risk to help them. Brabazon recounts a day in Liberia when a doctor treating rebels was accused of being a government spy. A rebel leader dragged the man away at gunpoint, and Brabazon, who already had witnessed executions in Liberia, was convinced he was about to shoot video of another. Hetherington was shooting video right next to him and stepped in to grab the gun hand of the rebel leader. He talked the man down, telling him not to shoot the doctor because he was the only medic the rebels had to tend their wounded. "That for me more than anything demonstrated Tim's courage, bravery and central humanity," Brabazon said. That wasn't another picture or part of the story for him. That was something that he needed to involve himself in as a human being with a very specific and concrete outcome. That person survived and was able to continue treating the wounded. That's how Tim saw war. Hetherington had talked about leaving combat coverage behind, starting a family and settling down in a less-dangerous lifestyle. Though Hetherington had called Libya his last trip to a war zone, Junger and Brabazon said they're not sure he would have followed through and given up the front lines despite new opportunities that "Restrepo" had opened for him. Junger and Hetherington had enjoyed the glitz of the Oscars, but they definitely felt out of place. "If you're in the Hollywood world, the red carpet is in some ways, it's a savage sort of competition for attention," Junger said. It's their combat zone, and we were just visiting it. ... We're kind of going to the zoo and seeing the pretty animals in some sense. Hetherington enjoyed it and was bemused by all the attention, Junger said. Yet throughout Oscar season, the Arab Spring revolts were erupting in Egypt, Libya and elsewhere in Middle East. Hetherington and Junger kept telling each other they should be there rather than parading around Hollywood in tuxedos. Soon after, Hetherington was there, back on the front lines. He is probably the only person who's managed to do this. He went from the red carpet at the Oscars to dead in a war zone in six weeks," Junger said. People who make films that go to the Oscars usually don't get killed in war zones, and people who go to war zones aren't often on the red carpet. And he managed to do both.