Season 4: Kill Site investigates the mysterious death of Christopher Whiteley, a case authorities ruled a mountain-lion attack despite evidence that didn't add up.

Season 3: Finding Dolores Wulff unravels the 41-year-old mystery of a mother who vanished one night from her home in a small California town.

Season 2: Unnatural Causes investigates the worst serial killer in Dallas history and the cracks in the system that helped him get away with murder again and again ... until one woman survived.

Season 1: The Labor Day Ghost investigates the chilling, unresolved murder of Shelley Salter Watkins, a young mom who was found dead in the Trinity River in Texas.