[mysterious music plays]

[phone dials] I called Mr. Allen.

[line ringing] I — I’m thinking in my mind, “OK, here we go.”

[suspenseful musical flourish plays] “Mr. Allen, were you the Zodiac?”

[echoing]

[menacing music plays]

Reporter: San Francisco has a killer in its midst. He had this black hood on, little slits in the eyes.

Man 1: He goes around killing people, by rope, by gun, by knife. And he says, “I’m gonna call myself Zodiac.”

Man 2: American law enforcement had never seen anything like this.

Woman 1: It turned into a public obsession. The TV shows, the books, the movie.

Zodiac: I want you to print this cipher on your front page. “Zodiac was different. He got away with it.”

[guns firing] You don’t want to believe the worst in somebody you trust your kids with. I thought, “There’s no way that it could be him.”

Woman 2: My sister and my brothers’ lives were molded by him. I had no idea how much my mother kept us out of the loop.

Woman 3: We started connecting the dots. We realized we had been to all the murder sites before the murders.

[music intensifies] You got people that are close to you, that can lie so easy.

Man 3: Mr. Allen paid different attention to the girls. I mean, he was my hero. We were determined to find out the truth. I’m not good at puzzle-solving, but I don’t give up.

Woman 2: The families of the victims should know. They have to know the whole story.

Man 4: I really thought I knew him …

[music stops] … but I didn’t.

[menacing music resumes]