A Knock On The Door

Detectives Revisit 1982 Murder Mystery

(CBS)  Melinda's new story of the murder was the end for Mark and Kristina Mangelsdorf’s quiet life in Pelham.

"It was just about exactly 10 o'clock. The phone rang, and Mark answered it. The person just said you know, 'This is Detective Hinds from the Pelham Police Department. Could you come downstairs, please.' We knew what they were there for," recalls Kristina Mangelsdorf.

Living with the cloud of suspicion for 23 years, Mark knew this day could come. But for Kristina, there was no preparing for what happened next.

"The minute Mark opened the front door, I mean, there they were and the handcuffs were on him like that. And they walk him off within about 30 seconds," she recalls. "I was busy looking at the detectives saying, 'Wait, you know, can I kiss him goodbye?' What do I do now?"

Mangelsdorf was arrested and escorted back to Kansas to face murder charges for the 1982 slaying of David Harmon. Charged with first-degree murder and conspiracy to commit murder, he faced the same charges as Melinda.

Just one week after Mark's arrest, Melinda went on trial for the murder of her first husband. By her side, showing support, was her current husband.

In spite of the dramatic interrogation tapes, prosecutor Morrison knew that getting a conviction after 23 years would be tough. He began by setting out to establish a motive for the crime.

Morrison set out to prove a case largely built on circumstantial evidence - evidence of an alleged love affair and lies.

Melinda had said she was in bed while her husband was being beaten to death, but prosecutors showed her pillow, covered in blood splatters.

Then there was her claim she was knocked out for more than hour. "That doesn’t fit at all. In fact, she didn't have any real injuries other than a tiny bruise on her cheek," Morrison said.

Prosecutors began unraveling her story of what happened that night, weaving a different story.

Prosecutors produced a stack of cards and letters from Melinda found in Mark's apartment, suggesting signs of an intimate relationship.

As the evidence mounted, it was the 2001 police videotape that cemented the prosecution's case against her and Mark.

As prosecutors slowly built their case, Melinda's defense team knew they had to confront the allegations of an affair and murder head on. To do that, they turned to one of the persons at the center of this case to testify: Mark Mangelsdorf.