The pair of detectives who knocked on Mark Mangelsdorf's door in suburban Pelham, N.Y., on April 4, 2004, saw nothing out of order. "He was doing his taxes. All his papers were on the table," says Pelham Det. Rick Deere of Mangelsdorf, a Harvard MBA, successful corporate consultant and married father of four. Mangelsdorf's calm may been genuine; after all, he had evaded arrest for most of his adult life. But within minutes police booked the 45-year-old suspect for the 1982 bludgeoning murder of one of his closest friends, a crime hatched, prosecutors say, in the heat of a love triangle set on the quiet campus of a Kansas Bible college. "Considering where we came from," says Paul Morrison, the Johnson County, Kans., district attorney who was one of the first to visit the ghastly crime scene and stayed with the case until its completion, "I think we got peace and justice."

Morrison says he will never forget the morning of Feb. 28, 1982, when as a young assistant D.A. he beheld the body of David Harmon, a 25-year-old banker beaten to death in his bed in Olathe. "You couldn't tell if it was a man or a woman, 10 years old or 80," says Morrison. Harmon's wife, Melinda, told police that two African-American intruders had bludgeoned her husband, dragged her downstairs, demanded the keys to David's bank, then knocked her cold. An hour later she awoke and ran next door for help.

The last part was true, say the neighbors, Richard and Gail Bergstrand, who lived in an adjoining duplex. With only a thin wall separating their bedroom from the Harmons', the Bergstrands had been awakened by the sound of the violent attack. "The noise was just so loud and alarming," says Gail. An hour later, when Melinda pounded on their door and asked for help, Gail was happy to oblige. But in retrospect, she says, she couldn't help but notice that the young woman seemed strangely calm. "I'm thinking how I'd react if my husband was just bludgeoned beside me. She said, 'Call my uncle,' and gave me the number. Nobody answered, and she said, 'Oh, that's right; they're out of town,' like when you call the pizza place and remember they're closed. Then she asked if I would call Mark."

Melinda meant Mark Mangelsdorf. At the time, he was the student body president of MidAmerica Nazarene University in Olathe, a small religious college where Melinda was secretary to the dean of students. Mark and Melinda struck up a friendship—its precise nature remains unclear—and soon the handsome top student was a fixture at the Harmon home, a friend to wife and husband alike. On the night of the murder, Mangelsdorf quickly arrived at the scene and comforted Melinda. Gail Bergstrand accompanied them to the police station. "In the police car, she said to him, 'I am just so sorry,'" she recalls. "And he said, 'You have nothing to apologize to me for.' I thought that was odd."

Not as odd as Melinda's story, which authorities, on reflection, found flimsy. Why was David beaten so savagely and she just slightly injured? Why, if a pair of robbers had taken her husband's bank keys, did they fail even to try to rob his bank? Suspicion focused on Melinda and Mangelsdorf, especially after police found what appeared to be love letters written by her at Mark's apartment. But with no concrete proof of an affair, and little other physical evidence, the case faded. Mangelsdorf received a standing ovation at his graduation ceremony—a show of support from his fellow students—and went on to Harvard. He married twice, most recently to Kristina Mangelsdorf, 36, with whom he has a 2-year-old daughter and a new baby, and held high posts at Pepsi-Cola and other companies. Melinda, who left town for good shortly after David's funeral, married Columbus dentist Mark Raisch. They have three children.

Decades would pass before new technology helped to reopen the case. In 2001 Olathe detectives Bill Wall and Steve James became interested in DNA testing and began a review of the police's cold cases, including the most intriguing: the Harmon murder. Yet in the end, it wasn't science but intuition that jumpstarted the dormant case. On a hunch, in December of that year, James and Wall went to Ohio to visit Melinda Raisch. "She could have shut the door in our face and said take a hike," says Wall. Instead she told them a new account of the murder night. "She said one guy, not two, came in and nobody grabbed her. She saw a shadowy figure beating her husband. Steve and I were looking at her like, 'Holy smoke,'" says Wall. The detectives flatly told Raisch they believed she killed her husband. Then came the breakthrough: Raisch allegedly told the cops she had "felt the presence of Mark Mangelsdorf" that night. "She said she 'knew it was him in her heart,'" says Wall, and later added that the brutality of the crime drove her to end the relationship.

In May 2005 a jury in Olathe convicted Raisch for the murder of David Harmon, based largely on her shifting account of his death. Only after the sentence was delivered, however, did she fully open up, confessing to prosecutors that she and Mangelsdorf were in love and had made a pact to murder her husband. Perhaps in response to her belated confession, Mangelsdorf—who was charged as her co-conspirator—pleaded guilty to second-degree murder charges on Feb. 13 of this year. He acknowledged that he participated in the crime without admitting he wielded the murder weapon, as Raisch maintains. Both await sentencing in May; because of deals cut with prosecutors, they face sentences as short as five years.

Interviewed at the couple's $2 million house in Pelham on Feb. 17, Kristina Mangelsdorf, a Pepsi executive, defended her husband, now out on bail: "We're doing fine. Mark is the strongest person I know." But John Harmon, the victim's father, sees Mangelsdorf in a different light. "This destroyed our family. David was my only son," he says. Just a few weeks after Melinda Raisch was charged, his wife, Susie, died of a blood clot. "At least," he says, "she died knowing something would be done."

  • Contributors:
  • Lisa Barron/Olathe,
  • Diane Herbst/New York,
  • Michelle York/New York.