The classified advertisement was unremarkable by the standards of Copenhagen's newspapers in the summer of 1920. A young, unmarried woman named Karoline Aagesen had placed it herself, seeking a loving family to adopt her newborn daughter. She was poor, she was unmarried, and in Denmark in 1920, those two facts together could define and diminish a woman for life. The ad was an act of desperation masquerading as pragmatism.

A woman responded promptly, presenting herself as warm and capable, a professional in the quiet business of finding good homes for unwanted children. Her name was Dagmar Overbye. She accepted the baby, accepted the fee, and sent Aagesen away reassured.

When Aagesen returned the following day, seized by a mother's instinct she could not suppress, Overbye told her she simply could not recall the adoptive family's address. The explanation made no sense. Aagesen went to the police.

What investigators found inside Overbye's apartment on Enghavevej, in the working-class Vesterbro district of Copenhagen, would become the most disturbing crime scene in Danish history. Blood-stained baby clothes. Charred bone fragments. And sifted from the cold ashes of the masonry stove, unmistakable in its smallness and its horror: a child's skull.

Dagmar Johanne Amalie Overbye was born on April 23, 1887, in Vedslet Parish near the village of Assendrup, not far from Aarhus, in the Skanderborg region of Denmark. Her parents, Sean and Anne Marie Overbye, were poor farming people; the land was modest and the margins were thin. There was nothing in the outward circumstances of Dagmar's childhood to predict what she would become, though those who later studied her history noted early signs of a temperament that troubled those around her.

She was twelve years old when she was caught stealing a purse from a neighbor. It was a petty crime, and she was a child, but her parents' response was decisive: they sent her away to work as a farm laborer on the island of Funen, off Denmark's western coast. She was still a girl, and she was gone.

The years between her childhood expulsion and her arrival in Copenhagen are not well documented, but the emotional architecture they built seems clear enough in retrospect. Dagmar Overbye grew up understanding that children who were inconvenient could be dispatched. She grew up knowing what it felt like to be the problem that needed solving.

In 1912, she gave birth to a daughter of her own, out of wedlock. The child disappeared. Investigators who later examined her case suspected she had killed this infant herself, though the evidence was insufficient to prosecute her for it. It may have been her first.

By 1915, Overbye had relocated to Copenhagen, settling in Vesterbro, a dense, working-class neighborhood of narrow streets and cramped apartment buildings, inhabited largely by factory workers, laborers, and the city's poorest families. It was, in its way, the ideal location for what she had in mind.

She established what amounted to a private adoption brokerage, informal and entirely unregulated. Denmark in the early twentieth century had no meaningful legal framework governing the placement of children born out of wedlock. Unmarried mothers, many of them domestic servants or factory workers who had become pregnant and faced social ruin, had almost nowhere to turn. Overbye offered them a solution: pay a one-time fostering fee of approximately 200 kroner, hand over the child, and the baby would be placed with a suitable, loving family. No questions. No paperwork. No consequences.

It was a lucrative arrangement, and she was good at the performance it required. She was calm, she was businesslike, she inspired a confidence that the mothers who came to her door desperately wanted to feel. Some of them may have suspected that the arrangement was too clean, the promises too smooth. But they were out of options, and she was there.

What happened after each mother walked away was methodical and merciless. Overbye killed the infants entrusted to her care by strangulation, by drowning, by smothering, by poisoning with ether. Some, investigators would later determine, she burned alive in the masonry stove that heated her apartment. The bodies she disposed of in whatever way was most convenient: incineration in the stove, burial in the building's garden, concealment in the loft above her rooms.

She kept photographs. When police searched her apartment following her arrest on September 12, 1920, they found images of approximately twenty naked children, all believed to be victims. The photographs were not trophies in any theatrical sense; they were records, almost bureaucratic, which somehow made them worse.

The full scope of her killing spanned, by her own account, from 1913 to 1920. She confessed to sixteen murders. Police, working backward through years of missing infants and grieving mothers who had never asked questions because they had been afraid to, could recover physical evidence confirming nine deaths. Nine was the number that went to trial. Sixteen was the number she carried.

Her exposure, when it came, was almost accidental in its simplicity. Karoline Aagesen's classified advertisement, her instinct to return for her child the following day, her decision to go to the police rather than accept the story she had been told: any one of those choices, unmade, might have allowed Overbye to continue.

The trial began in early 1921 and drew the sustained, horrified attention of the entire country. The courtroom testimony was a catalog of methods and remains. Investigators described the charred skull, the bone fragments, the stained clothing. They described the photographs. Overbye's defense lawyer argued that she had suffered abuse as a child, that her crimes were the expression of a damaged person rather than a calculating predator. The court was not persuaded.

On March 3, 1921, Dagmar Overbye was convicted of nine counts of murder and sentenced to death. It was the first death sentence imposed on a woman in Denmark since 1861, and only one of three such sentences handed down to women in Denmark across the entire twentieth century.

The sentence was commuted by King Christian X on May 25, 1921. The king reportedly expressed the view that an enlightened Denmark did not put its women to death. Like the two other women sentenced to death in Denmark during that century, Overbye was reprieved. She was remanded to Vestre Fængsel, the Western Prison in Copenhagen, to serve a life term.

She never left. Dagmar Overbye died at Vestre Fængsel on May 6, 1929, at the age of forty-two. Some sources attribute her death to kidney disease. Denmark would abolish the life sentence just one year later, in 1930. She did not live to see it.

What Overbye's case did produce, with a directness that felt almost like reparation, was legislative change. In 1923, the Danish government passed landmark legislation establishing public foster homes and legal oversight for children born out of wedlock. For the first time, Denmark had something resembling a real child welfare system. The orphaned, the illegitimate, the inconvenient children who had existed entirely outside the protection of the state were, at last, within it. The law came too late for the children on Enghavevej. It came because of them.

In the Danish language, there exists a word for people like Dagmar Overbye: 'englemagersken,' the angel maker. It was a term used at the time for those who killed infants, rooted in the dark Victorian euphemism that dead children became angels. It is her enduring nickname in Danish true crime history, and it contains within it a kind of bitter irony: the language itself softened what she did, wrapped it in wings and light, before the full ugliness could be spoken plainly.

The 122-page transcript of her trial is preserved at the National Danish Archives. Physical evidence and case materials are held at the Politihistorisk Museum, the Museum of Police History, in the Nørrebro district of Copenhagen, not far from the neighborhood where she operated. Her photograph, taken by police around the time of her arrest in 1920, shows a plain-faced woman in dark clothes, her expression giving nothing away.

Her story has continued to exert a pull on artists and storytellers for a century. Danish author Karen Søndergaard Koldste wrote a novel titled 'Englemagersken.' A stage play, 'Historien om en Mo(r)der,' was performed at Teatret ved Sorte Hest in Copenhagen. In 2024, filmmaker Peder Pedersen released the horror film 'Englebørn' (released internationally as 'Lost Angels'), which premiered at the Chicago Horror Film Festival.

But the fullest and most acclaimed artistic reckoning with her legacy arrived in 2024 with 'The Girl with the Needle' ('Pigen med nålen'), a Gothic historical film directed by Magnus von Horn, in which Trine Dyrholm portrays a character based on Overbye. The film premiered at the 77th Cannes Film Festival on May 15, 2024, to critical acclaim. It was nominated for Best Foreign Language Film at the 82nd Golden Globe Awards and served as Denmark's official submission for Best International Feature Film at the 97th Academy Awards, receiving an Oscar nomination in that category.

Something about her case resists easy resolution, even now. The question that lingers is not about guilt or method or even motive, which was financial and almost mundanely transactional. The question is about the system that made her possible: the absence of oversight, the desperation of the women who came to her, the complete legal invisibility of the children she killed. Dagmar Overbye did not create the conditions that made her crimes so easy to commit for seven years. She exploited them, with extraordinary and terrible efficiency.

She is remembered in Denmark as 'Englemagersken,' the Angel Maker, the country's most prolific known serial killer, its first recognized female serial killer. The children she killed had no names in the public record. They were illegitimate, informal, off the books. They had been handed to a stranger and they vanished, and no one came looking, because no one was watching.

Denmark is watching now. It has been, in law if not always in practice, since 1923. That is the only monument those children have.