This is fact: Marilyn Sheppard was murdered in 1954. The rest of the crime is a haunting question mark. The Sheppard case led to the infamous trial- and re-trial- of her husband, Dr. Sam Sheppard, and launched the legal career of lawyer F. Lee Bailey. But who was the killer? Dr. Sheppard's insistence that a mysterious stranger was the real murderer led to his eventual acquittal years after the murder and inspired the plot of The Fugitive. Now, nearly 50 years later, NOVA reopens America's most intriguing unsolved murder case.

Play modern-day detective with a detailed reconstruction of the Sheppard house, access little-known evidence, and hear insights from such forensic experts as DNA specialist Barry Scheck, a member of O.J. Simpson's legal "Dream Team." Like an intricate puzzle, clues come together to overturn previous assumptions about the killer and point to an entirely new, still unknown, suspect. If you love a good mystery, you'll be fascinated by The Killer's Trail.