Los Angeles January 15th, 1947 [music] A woman walking on Norton Avenue stopped when she noticed something in a vacant lot. She thought it was a mannequin. It wasn't. The body of 22-year-old Elizabeth Short had been drained completely of blood. Cut in half at the waist [music] with surgical precision. Posed, cleaned, arranged [music] like a display. Elizabeth had come to Hollywood with a dream. She wanted to be an actress. Six days before [music] her body was found, she was dropped off at the Biltmore Hotel. She walked out the front door. >> [music] >> And no one ever saw her alive again. The press called her the Black Dahlia. Her murder was front-page news [music] for 35 straight days. Over 150 suspects were [music] investigated. Then the killer sent letters to the newspapers. Made from cut-out clippings. One read, "Here is Dahlia's belongings." [music] Inside, her birth certificate, her address book. [music] He had kept them. Three years later, police secretly [music] bugged the home of a prime suspect. A brilliant doctor, IQ of 186, one of the most powerful men in Los Angeles. >> [music] >> And on that tape, "Supposing I did kill the Black Dahlia. They can't prove it now. They can't talk to my secretary anymore because she's dead." He left the country weeks later. He was never charged. He died in 1999. Then, his own son, a retired LAPD homicide detective, spent years trying to prove his father was innocent. And became convinced he was the killer. Elizabeth Short's murder remains officially unsolved. The physical evidence has disappeared from LAPD files. Follow for the full story.