conrad and heidi truman had a powerful connection a deep love envied by others. then one fateful night the young couple was jolted by unforeseen tragedy when heidi was killed by a single gunshot to the head. in the after math, fingers were pointed, but were they aimed at an innocent man? here's josh mankiewicz with "as night fell." >>> they seemed so incongruous. the soaring majesty of utah's mountains and the story of a beautiful woman struck down in her youth. it was a lot of things. tragic. crushing. stunning. but was it an accident? or a suicide? or a murder? police felt they knew. but as most cops will tell you, both the evidence and the jury have their own stories to tell. and the answer is not always so clear. certainly, that is true for this story. and quite possibly for the woman at its heart. her name, heidi wagner. >> as a baby, she was savored, everybody loved her. she could do no wrong. >> autumn was one of heidi's four sisters. >> she was just special. you know, she'd walk into the room and she's ready for that good time. >> reporter: heidi grew up w