A Knock On The Door

Detectives Revisit 1982 Murder Mystery

(CBS)  This story originally aired April 15, 2006. It was updated on July 5, 2007.

David Harmon was bludgeoned to death on Feb. 28, 1982, while lying in bed next to his wife in Olathe, Kan. The murder, which shocked this quiet, peaceful town, went unsolved for more than two decades.

Police had their suspicions in the case. They questioned the victim's wife and a friend of the couple. However, in the end, the investigation went nowhere.

But as Hannah Storm reports, a fresh look at old evidence and a knock on a door would change everything.

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Today, Olathe is a major crossroads, a fast-growing suburb of Kansas City and home to a large conservative Christian community. But back in 1982, it was just a dot on the map.

"In 1982 this was a community where you didn't have to lock your doors, basically. I know that's a cliché, but there was not a lot of danger," recalls Andy Hoffman, who was a reporter for Olathe's "Daily News."

"The people who lived here were God-fearing," says Hoffman. "They believed in the Bible, and when this murder happened it changed the landscape of the community."

There weren't a lot of homicides in Olathe, and the unsolved murder of David Harmon was a nightmare that stayed with residents for more than two decades.

Detective Bill Wall says he heard about the case for the first time in the early 1990s, when he was a young patrol officer. "It was always kind of a case that had never been solved, and it's kind of a legend throughout the department," says Wall.

The case might have stayed cold if not for a simple request in 2001 and some new technology.

"The crime lab came down, and they had some time and they wanted to use their DNA expertise. 'You got any old cold cases?' And we had one," Wall explains.

The Harmon case moved out of the evidence vault and into the hands of Detectives Wall and Steve James. They went through all the evidence to learn what happened back in 1982.

There were accounts from police officers, including J.W. Larrick, then 27, and one of the first responders. He found Harmon's body upstairs in the master bedroom. "It is the most gruesome crime scene that I've seen in 28 years of being a police officer. He was just massacred," Larrick recalls.

Harmon had been beaten repeatedly with a blunt object.

Wall says there was blood everywhere in the bedroom. "I think this is a classic case of an overkill," he says.

Harmon's wife, Melinda, was the only witness. She told police that two men, possibly black, had broken into their duplex, and said she was awakened by the sounds of someone beating her husband.

"And then, all of a sudden she is pulled out of bed and taken downstairs. She hears one intruder say to the next, 'I think you hit him too hard. You may have killed him,'" Det. Wall explains.

She said they demanded the keys to the bank where David worked, then knocked her out.

Melinda told police that when she came to, she ran next door for help. Her neighbor called the police. Then Melinda asked her to call her friend Mark Mangelsdorf.

Mangelsdorf was practically a member of the Harmon family; he often had dinner and hung out with the couple. Their friendship began at MidAmerica Nazarene University, where Melinda was a secretary.

"She was not much older than our students," recalls Don Stelting, who was Dean of Students and Melinda's boss. "Part of the responsibility of my office staff was to make a warm front door for the students. She was a friendly person and she worked hard at that."

One of the students she befriended was Mangelsdorf, the student body president. Melinda introduced Mark to David.

"I mean, David was in many ways like a big brother to me. You know, he took me under his wing," says Mangelsdorf.

They two men shared a passion for sports, business and their church.