“Population Zero” (*** out of four) was an incisive mockumentary about the investigation into a series of murders at Yellowstone National Park and how the murderer who confessed was freed and dismissed due to a legalistic loophole within the courts. But film goes even deeper into the ruptures that occurred within the family’s small town and how the killer was motivated by the big-business affects of fracking. Engrossing story holds you attention from start to finish. How “real” it is can be debated and may effect your enjoyment but film is still fascinating and well-made.