It had been four decades since the girl in the little blue dress seemed to vanish off the face of the earth. Now her mother Donna Prentice was about to stand trial for her murder.

Dick Pulsifer, Michelle’s father, was determined to be at every hearing -- no matter how routine or insignificant. Each time, he drove 270 miles with his wife Cathe from their home in Las Vegas to Orange County -- a trip that would sometimes take four to five hours each way.

He wanted to see Donna in court, hoping to finally hear the truth he felt she'd kept from him for so long.

Dick Pulsifer: This whole thing from '69 on has been nothing but a lie. She's lied to me the whole time, you know? “Michelle's alive. She knows who I am. She's going to graduate when she's 18. If she wants you to be in her life, she'll call you.”

"A little girl lost" is how prosecutor Larry Yellin described Michelle to the jury in his opening statement.

On the first day of trial, Rich Jr. testified about that night when he was 6 years old, when Michelle had asked to be hidden. The last time he'd seen her alive.

After an array of other witnesses, Yellin let the jury hear Donna’s side of the story in her own words. He wanted to give her enough rope to hang herself. They listened to an audio cassette of her interview with Ed Berakovich, an investigator with the district attorney's office.

Donna stuck to her story about how they'd taken Michelle to Mike's mother's home while the rest of the family relocated. But she also tried to explain away Rich Jr.'s claim that he'd overheard her one night using the words Michelle and dead in the same sentence.

(Police interview tape)

Donna Prentice: He at one time said that he had, uh, overheard me saying that she was dead.

Investigator: That he overheard you say that?

Donna Prentice: And that he heard, yes...

Investigator: Yes.

Donna Prentice: -- that he heard me say this. And I said, well, I disagreed with him. As far as I was concerned because of the length of time that she was dead.

Investigator: OK.

Donna Prentice: Because I’m not -- I was not going to go through anything to find her. I was not going to—

Investigator:  Why would you think she was dead?

Donna Prentice: No, no, I didn't say that.

Investigator: OK.

Donna Prentice: I said she was dead to me...

Investigator: Yeah.

Donna Prentice: ...because I was not bringing her into my life.

Donna also defended her seeming indifference to what had happened to her own daughter.

(Police interview tape)

Investigator: It's hard to believe that you never, ever, I mean -- how, you know, all these years about your daughter, I mean aren't you curious --

Donna Prentice: I know.

Investigator: -- of where she is or if she's alive or who's she with?

Donna Prentice: I know, I know, I know … No.

Investigator: OK, so you kind of just erased her from your mind?

Donna Prentice: Uh-huh.

In the interview, Berakovich asked Donna seven times about Michelle’s whereabouts. And each time, she told him she thought her daughter might have been taken to Canada by Mike's mother. After all, she said, there was a girl named Michelle -- about her daughter's age -- among Mike's relatives there.

Video   A mother’s surprising admission March 14: When a missing girl’s mother responds to questions, police get surprising answer to their questions. Dateline NBC

But Detective Berakovich poked a giant hole in Donna’s theory.

(Police interview tape)

Investigator: There's a sister that has a daughter Michelle in Canada, but it's their daughter. They just happen to have a daughter that's Michelle.

Donna Prentice: OK.

Investigator: I know it's a lot years gone by. I got a feeling this has probably been eating at you for all these years. It's had to be.

Donna Prentice: That was -- that was the last --.

Investigator: OK.

Donna Prentice: That was the last thing I could have hoped for. (crying)

Was Donna crying because she finally realized that her daughter was dead or was there something else?

Larry Yellin: She could be crying for herself because investigator Berakovich just blew up her alibi.

What kind of mother could so callously, so matter-of-factly describe putting her little girl out of her life for so many years? Prosecutors argued only one that was guilty of killing her. But remember the state had no body, no eyewitnesses to a crime, no physical evidence that a murder had even occurred.

The defense was about to present an alternate killer. In essence, they would put Mike Kent on trial. Jurors would hear new details about the marriage -- and a haunting tape with his claims about exactly what happened to little Michelle in the summer of 1969.

MORE FROM CRIME STORIES

Crime stories Section Front

Justice halted: The murdered prosecutor Hard lessons: Teacher-student love turns lethal Bullies caught on tape: Aggressors, or victims? Clark Rockefeller: Famous name, infamous life How the phony French 'Rockefeller' conned Americans The crossbow incident Mystery of the missing millionaire The devil's business Deadly intentions Murder on the mind Crime stories Section Front   Add Crime stories headlines to your news reader: