It sounds like fiction—like a murder mystery in a worn paperback novel. A wealthy woman is murdered in her bed, smothered with a pillow in the landmark lakeside mansion built by her parents. Her nurse is also killed, bludgeoned with a candlestick. Investigators quickly identify two suspects with a classic motive: struggling financially, the suspects stood to inherit millions upon the victim’s death. No witnesses survive, and the cops in a small northern Minnesota city have to make their case based on purely circumstantial evidence.

The grotesque story is nonetheless a true one that unfolded almost 40 years ago now: Duluth’s Glensheen murders, an atrocity that riveted the region for years. Though one of the suspects was convicted, and later signed a confession, some elements of the crime remain mysterious, and it has persisted as a source of continued fascination.

Glensheen, a new musical about the crime written by acclaimed playwright Jeffrey Hatcher with music by the Suburbs’ Chan Poling, opens Oct. 3 at St. Paul’s History Theatre. Poling was recruited by Hatcher, who had been asked by the theater to write a play based on the Glensheen case; Hatcher told Poling he only wanted to do the play if it could be a musical. “I burst out laughing,” says Poling. “I thought that was kind of brilliant.”

Although he’s best known for his work with the Suburbs, Poling is no stranger to the stage. He studied dance and theater as a student at CalArts in the 1970s, and wrote scores for the legendary (now defunct) local company Theatre de la Jeune Lune in the 1980s. Poling is channeling these past experiences for Glensheen.

“I started out with a Gothic feel, really influenced by Cabaret, Chicago, and Sweeney Todd,” he says. “[It’s] a very rich Sondheim sound.

“You find yourself not knowing what play you’re in,” Poling continues. “You think you’re in a Gothic murder mystery, and then humorous elements come in and you end up popping into different worlds.”

If you’ve heard of the play or visited the Glensheen mansion in Duluth—operated by the University of Minnesota as a museum and event space—you may have wondered to yourself: What exactly happened on that summer night in 1977?

The murders

The murders were truly reprehensible: attacks of deadly violence committed on two vulnerable, unsuspecting victims. The primary victim, Elisabeth Congdon, was 83 years old. A stroke had left her mobility and speech seriously impaired, requiring full-time medical supervision. Her nurse that night, 66-year-old Velma Pietila, had just retired and was looking forward to relaxing and traveling with her husband; she’d been convinced to return to work for one more night because the regular nurse was on vacation.

Duluth police were called to the mansion on the morning of June 27, 1977, after staff discovered the two women dead. The crime immediately attracted national attention. Elisabeth was the last surviving child of mining magnate Chester Congdon, who built Glensheen in the first decade of the 20th century and was reportedly the richest man in Minnesota when he died in 1916. Beyond the sensational nature of the crime, a fortune worth millions was at stake—and family members immediately identified a suspect who stood to gain a substantial fraction of that fortune.

Marjorie Congdon Caldwell was one of two daughters adopted in the 1930s by Elisabeth, who never married. From an early age, Marjorie showed signs of devious behavior, and as a teenager she was diagnosed as a sociopath. Intelligent and often charming, Marjorie married and had six children before the marriage ended amid stresses exacerbated by her exorbitant spending. By 1977, she was living in Colorado and married to her second husband, Roger Caldwell.

Relations between Marjorie and her family members were highly strained, and the Congdon estate closely monitored all communication between Marjorie and her mother. Suspicions about Marjorie were already heightened by a 1974 incident in which Elisabeth became dangerously ill after eating a sandwich made by her daughter. When Elisabeth was found murdered, it didn’t take long for the investigation to zero in on the Caldwells.

Police suspected that Roger Caldwell flew from Colorado to Minneapolis, drove to Duluth, and committed the murders under cover of darkness. No witnesses judged reliable by the police had seen Roger in Colorado on the night of the murders, and Marjorie told several inconsistent stories about her husband’s whereabouts. When jewelry matching that taken from Glensheen, and a convenience store receipt from the morning of the crime printed in the Minneapolis–St. Paul Airport, were found in the Caldwells’ hotel rooms, authorities arrested Roger and charged him with the murders.

The trials

The case went to trial in the searing summer of 1978. Despite prosecution having only circumstantial evidence to present, Roger was convicted and handed two consecutive life sentences.

Four years into his sentence, though, Roger Caldwell walked out of prison, never to return. His conviction had been overturned by the Minnesota Supreme Court after fingerprint evidence used in his trial was called into serious question during Marjorie’s own criminal trial in 1979—in which she was acquitted of her alleged role in planning the murders.

With Roger out of prison under supervision and a retrial looming, authorities decided to strike a deal rather than risk an acquittal. In 1983 Roger Caldwell confessed to the Glensheen killings, pleading guilty to two counts of second-degree murder. In a plea bargain, the remainder of Roger’s prison sentence was dismissed as authorities hoped his confession would implicate Marjorie—though that didn’t turn out to be the case.

In 1988, Roger took his own life, leaving a suicide note that read in part, referring to the Glensheen victims, “I didn’t kill those girls.”

There’s a lot of ground to cover, says Poling, around why the trials of Roger and Marjorie ended so differently. “There are a million little convoluted rivers that flow from that,” he says. While darkly comic elements pepper the musical, Poling emphasizes that he and Hatcher have been respectful of the victims. As far as Marjorie and Roger: “They’re fair game. What they did is public record.”

Marjorie is now the same age her mother was when her mother was murdered. She remains a free woman—though she’s been twice convicted of arson or attempted arson, and served two sentences for those crimes. Additionally, two other men she’s been close to have died in what some have regarded as suspicious circumstances. Charges against Marjorie were dropped in the first case and never filed in the second.

Poling says he and Hatcher are “acutely aware” that audience members for Glensheen will include members of the victims’ families, investigators who worked on the case—and possibly even Marjorie Congdon Caldwell. “We hope Marjorie doesn’t show up at the theater with a box of matches,” Poling says. “The family has written some letters, and we’ve had discussions. A big contingent are coming in opening night—they’ve got their tickets already.”

Suzanne Congdon LeRoy, one of Marjorie’s daughters, recently published a biography of her late grandmother, highlighting Elisabeth’s philanthropic legacy. Suzanne is estranged from her mother, telling MinnPost interviewer Amy Goetzman in 2014 that the last she’d heard, her mother was calling herself Marjorie Hagen and living in the Southwest. She added that she hasn’t had contact with her for 40 years.

When Goetzman asked whether Suzanne fears for her safety, Suzanne answered that she’s taken “all the necessary precautions.” Even so, she says, “You never turn your back.”

This article was produced as a part of a collaboration between 89.3 The Current and The Growler, a monthly craft beer lifestyle magazine covering the best stories in beer, food, and culture. Find this article online and in print in the October edition of The Growler.