On a warm June afternoon in 1868, a 24-year-old woman accepted a glass of lemonade from her nurse at a Geneva boarding house. Within moments, her pupils dilated grotesquely, her heart pounded violently, and reality dissolved into nightmare. That glass of lemonade broke open one of Switzerland's most disturbing criminal cases.

SEASON & EPISODE CONTEXT

This is Episode 9 of Foul Play Season 36: "Serial Killers in History," examining murderers from ancient times through the early 1900s. This season explores 15 cases spanning centuries and continents, revealing how serial murder predates modern criminology by millennia.

THE CASE SUMMARY

Between 1865 and 1868, Marie Jeanneret worked as a private nurse in Geneva and surrounding areas of Switzerland, moving between respectable boarding houses and private hospitals. Everywhere she went, patients died under mysterious circumstances. Eleven-year-old children. Elderly widows. Entire families.

Her method was both calculated and cruel. She used cutting-edge poisons for the 1860s—plant alkaloids like atropine from belladonna and morphine from opium poppies. These substances were so difficult to detect in corpses that she might never have been caught. She offered candy she called "princesses" to children. She served sweetened water to friends. She predicted deaths days before they happened—not because she had medical insight, but because she knew exactly when the poison would finish its work.

When authorities finally exhumed the bodies in 1868, they found chemical signatures of murder in decomposing tissue. The trial revealed at least six confirmed murders and perhaps thirty attempted murders. But the verdict the jury reached would create one of criminal history's most profound paradoxes—her case helped abolish the death penalty in Geneva three years later.

THE VICTIMS

Marie Jeanneret's victims weren't random—they were people who trusted her completely during their most vulnerable moments:

Marie Grétillat, 61, hired Jeanneret for what should have been a minor illness. She died in February 1867 after weeks of escalating agony.

Sophie Juvet, 58, died in September 1867 at the Maison de Santé hospital where Jeanneret worked as a nurse.

Jenny-Julie Juvet, Sophie's daughter, was only 11 years old. She loved candy and trusted the nurse who brought her special bonbons called "princesses." Before she died in January 1868, she begged her family not to let the nurse near her anymore. They thought she was delirious. She wasn't—she knew.

Auguste Perrod (around 80), Louise-Marie Lenoir (72), Madame Hahn, Demoiselle Gay, Demoiselle Junod, Julie Bouvier, and Jacques Gros (Julie's father) all died under Jeanneret's care between 1867 and 1868.

KEY CASE DETAILS

THE METHOD: Jeanneret used belladonna (deadly nightshade) and morphine as her primary weapons. Belladonna poisoning produces distinctive symptoms: grotesquely dilated pupils, rapid heartbeat, extreme light sensitivity, terrifying hallucinations, and eventually seizures and respiratory failure. Morphine suppresses breathing until victims simply stop inhaling—the death looks peaceful but is actually suffocation.

As a nurse, she had legitimate access to these substances and professional cover for every action. She mixed poisons into sweet items—lemonade, sweetened water, candy—because sugar masks the bitter taste effectively. For some victims, she administered lower doses over time, creating slow declines that mimicked natural illness. For others, she used massive doses intended to kill quickly.

THE BREAKTHROUGH: The case broke open when Marie-Catherine Fritzgès, 24, survived a belladonna poisoning in June 1868. Her doctor recognized the symptoms immediately and contacted authorities. Police searched Jeanneret's rooms and found bottles of belladonna extract, containers of morphine, and detailed nursing notes documenting every symptom, decline, and death—inadvertently documenting her own crimes.

HISTORICAL CONTEXT & SOURCES

The 1860s represented a turning point in forensic medicine. Swiss medical examiners used groundbreaking techniques to test tissue samples for alkaloid compounds in exhumed bodies—finding chemical signatures consistent with belladonna and morphine poisoning. This case marked one of the first instances where forensic medicine played a crucial role in securing a conviction in Switzerland.

The trial opened in Geneva in late 1868 with overwhelming evidence: poisoned bodies, survivors' testimony, bottles of poison, and Jeanneret's own nursing notes. On November 19, 1868, the jury returned a stunning verdict—guilty on all counts, but they recommended clemency. Instead of execution, Jeanneret received life imprisonment with hard labor.

Three years later, in 1871, the Canton of Geneva abolished the death penalty. Jeanneret's case was cited as a key example—a jury had looked at overwhelming evidence of serial murder and chosen mercy over execution.

RESOURCES & FURTHER READING

Swiss criminal history archives maintain extensive records of the Jeanneret case, including original trial transcripts and forensic reports that revolutionized poison detection methods. The case remains a standard reference in medical ethics courses throughout Europe, illustrating the catastrophic consequences of betrayed medical trust.

The Geneva State Archives houses original court documents from the 1868 trial. Swiss forensic medicine institutes continue to study the case as a landmark example of early toxicology and the systematic safeguards developed in response to healthcare serial killers.

RELATED FOUL PLAY EPISODES

If you found this episode compelling, explore other Foul Play cases involving Victorian-era poisoners and medical professionals who betrayed their sacred trust. Season 36 examines serial killers throughout history, from ancient Rome through the early 1900s, revealing how murder predates modern criminology and how society responded to unimaginable crimes.

Each episode of Foul Play combines meticulous historical research with victim-centered storytelling, honoring those whose lives were taken while examining the criminals who took them.

THE LEGACY

Marie Jeanneret's crimes fundamentally transformed Switzerland's approach to medical safety and criminal investigation. The case exposed critical gaps in poison control, leading to strict measures including detailed record-keeping of sales and mandatory identification checks. Background checks for medical staff became more thorough, references were more carefully vetted, and supervision was enhanced throughout Europe.

Perhaps most significantly, Jeanneret's case transformed public consciousness about the nature of evil. The idea that a healthcare professional could systematically murder patients while maintaining an appearance of respectability forced society to confront uncomfortable truths. The poisoner who took at least six lives became part of the movement that saved countless others from execution—the most paradoxical legacy imaginable.

ABOUT FOUL PLAY

Foul Play examines history's most compelling true crime cases with meticulous research and sophisticated storytelling. Hosts Shane Waters and Wendy Cee explore serial killers from ancient Rome through the early 1900s, focusing on victim-centered narratives that honor the dead rather than sensationalizing killers. Each episode combines atmospheric period detail with rigorous historical accuracy, transporting listeners to crimes that shaped criminal justice systems across centuries and continents.

CONNECT WITH FOUL PLAY

New episodes release every Tuesday at 5:00 AM EST. Follow Foul Play on social media for behind-the-scenes research, historical context, and episode updates. Visit our website for complete episode archives, source lists, and additional resources about the cases we cover.

CONTENT WARNING

This episode contains detailed descriptions of poisoning, murder of children, and medical betrayal. Listener discretion is advised. If you or someone you know needs support, resources are available through crisis helplines and mental health services.

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