A Knock On The Door

Detectives Revisit 1982 Murder Mystery

(CBS)  Investigators had always believed Melinda and Mark conspired to murder David so they could be together. Now Wall needed details about their romance to prove a motive.

"She said they were friends at first," recalls Wall. "Later on, as their relationship blossomed, she said that there became an emotional bond between the two of them."

Asked if she shared her innermost, deepest feelings, Melinda told Wall during the videotaped interview, "In a way that is inappropriate."

"She said that her feelings were inappropriate - and that her husband, David, would definitely not approve," says Wall.

But according to Melinda, Mark wanted more.

"Did he ever come out and say, 'I love you and I want to have sex with you?'" Wall asked Raisch during the videotaped interview.

"I would say so," she replied.

"She told me that she got the impression he (Mark) wanted her to get a divorce," says Wall.

With their romance established, Wall now needed Melinda to connect Mark to the murder.

"If you did not kill him, you know who did it. And we've been down that road. And now you're trying to lead me to believe…," Wall asked Melinda.

"Well, I know in my heart …," she said.

"You know in your heart what? That Mark did it?" Wall continued.

She replied, "Uh-huh, in my heart I know that."

She told Wall she didn't see Mark that night but sensed his presence, coming from the stairs.

"Why is she saying she felt Mangelsdorf's presence rather than, 'I saw him bludgeon my husband?'" Storm asked Wall.

"I just don't think she wanted to go there yet. She knew if she said that then, that would implicate her further," he replied.

Melinda wanted to know the consequences before giving up any more information, asking Wall, "I don't know where I stand." On the tape, she acknowledged there was a little more information she had.

Wall called D.A. Paul Morrison in Olathe and told him Melinda wanted to discuss a deal.

"And I remember tellin' Wall that I wasn't gonna buy a pig in a poke, because we didn't know exactly what she had to offer," recalls Morrison. "That in my opinion, she had already made some serious admissions, so let's not make any deals today that we might regret later."

After almost two decades of frustration, Morrison finally had a toehold. But it would take two more years of poring over every piece of evidence to make a case.

"You've got no statute of limitations on a murder case. So we had the luxury of makin' sure that we got our ducks all lined up as straight as we could before we went into battle," says Morrison.

In 2003, with those ducks lined up, Melinda was finally arrested and charged with her husband’s murder.

The news stunned Mangelsdorf. "It did surprise me, it caught me off guard. I thought that this thing had potentially run its course, and it of course had not," he told Storm.