When a rainforest-loving nun from Ohio gets assassinated in the middle of a land dispute between Brazilian ranchers and rainforest preservationists, something has gone terribly wrong. They Killed Sister Dorothy follows David Stang as he investigates the 2005 shooting of Dorothy Mae Stang, his sister. What follows is neither an overwrought, environmental preach-a-thon nor a Michael Moore stunt movie. Director Daniel Junge uses narration sparingly—provided by the ever-assuring voice of Martin Sheen, of course—to set the scene; then he lets news footage and interviews tell the story. In the subsequent courtroom chaos, one killer claims for a time to have pulled the trigger for the equivalent of $50. Shifting and conflicting statements abound. The pace moves at a steady clip until a dramatic twist: A defense attorney accuses the victim of being part of a U.S. conspiracy to take over native soil, always an incendiary and effective charge in Latin America. Yet in this posthumous portrait, Sister Dorothy comes off as less a martyr than a source of hope for a violent, troubled region. Harvard Exit, 807 E. Roy St., 448-2186, www.siff.net. $9–$11. 7 p.m. (Also: 4:30 p.m. Wed., May 28.) LAURA ONSTOT

Tue., May 27, 7 p.m.; Wed., May 28, 4:30 p.m., 2008