When Susan B. Anthony took the stage at New York’s Cooper Union on the night of December 1, 1868, the activist—already famous for helping organize the first groups of American women’s rights agitators—could spot some of the suffrage movement’s leading lights in the audience. There was Horace Greeley, the influential abolitionist who had taken up the suffrage cause. There was Elizabeth Cady Stanton, Anthony’s friend and partner in agitating for votes for women. And there were scores of other influential women who worked and marched and demanded the vote.

But Anthony wasn’t there to fight for the ballot—she was there to demand the release of a convicted murderer from prison. As she took the stage, she told the audience about the case of Hester Vaughn, a woman tried and convicted of murdering her own baby. But Vaughn wasn’t a cold-blooded murderer, Anthony insisted, she was yet another victim of a system that denied women their basic human rights.

At the time, the story of a poor, unmarried domestic servant was an unlikely cause célèbre. But Vaughn became the centerpiece of a shocking infanticide trial that exposed sexual harassment, gender inequality and the limited legal rights of women—issues that attracted the sympathy of the leaders of the growing women’s rights movement.

It all started in 1868 when a dead baby was discovered in the apartment of Hester Vaughn, an English immigrant working as a domestic servant in Philadelphia. Vaughn had come to the United States to meet her fiancé, a man who was in fact married to another woman and abandoned Vaughn after she arrived in America.

Five years later, the unmarried Vaughn became pregnant by a man she refused to publicly identify. At the time, single mothers were doomed to life as social outcasts, and Vaughn gave birth to the baby alone and in secret in her apartment. But the infant soon died, igniting a sensational trial in which she was accused of murder.

In court, Vaughn testified that she had been seduced by her employer and then fired from her job for falling pregnant. Vaughn claimed that soon after giving birth she had fallen on the child, startled when her landlady entered the room with a pot of coffee. However, a different story emerged during the trial, in which she was accused of intentionally inflicting the fatal head injury.

After nearly a month of testimony, Vaughn was found guilty and sentenced to death by hanging. “Some woman must be made an example of,” the judgesaid at her sentencing, pointing out that infanticide was on the rise.

The story could have ended there—a wayward woman, a gruesome crime and a harsh punishment meted out by the Commonwealth of Pennsylvania. But Vaughn’s case caught the attention of suffragists including Susan B. Anthony and Elizabeth Cady Stanton. Under the auspices of the Working Women’s Association and their newspaper, The Revolution, they decided to agitate for Vaughn’s release, using her story as the lynchpin for a wider national conversation about the dangers faced by women in the workplace.

Vaughn’s story seemed a prime example of the everyday danger faced by working women in the mid-19th century. At the time, upper- and middle-class women were discouraged from working; instead, they were expected to rely on the financial support of fathers and husbands who were to protect them from the world outside the home. But working-class women, even married ones, had fewer options. They were the domestic workers, factory laborers and seamstresses who helped enable the lifestyles enjoyed by more affluent women like Anthony and Stanton.

The suffragists felt a keen responsibility to highlight the struggles of marginalized women like Vaughn and to fight for equal treatment for women in the workplace and society at large. Just like the judge who had sentenced Vaughn, the WWA saw her potential as a symbol for something larger.

The WWA decided to try to win Vaughn’s pardon and began working on a campaign that presented Vaughn in a better light than the sexually promiscuous murderer implicated by the guilty verdict. They played up the more sympathetic aspects of Vaughn’s case, publishing long accounts of her struggle in a new country, her seduction and abandonment by her boss, and her tragic account of accidentally killing her baby.

In articles with headlines like “A Sad Story,” which ran in the Canadian newspaper The Public Ledger in January 1869, they referred to Vaughn as “a desperate waif” and a naive girl who had been preyed upon and then discarded by a brutal system.

As time went on, Vaughn’s story was increasingly portrayed as one of rape and abandonment, though it remains unclear if she was in fact raped by her employer. Vaughn became a stand-in for all marginalized women, a victim so protective (or scared) of the man who abused her that she refused to accuse him. Vaughn, her advocates asserted, was proof that women did not have equal rights under the law—not even the ability to be tried by a jury of their peers, other women.

“What a holocaust of women and children we bring annually to the barbarous customs of our present type of civilization, to the unjust laws that make crimes for women that are not crimes for men!” Stanton wrote in a characteristically impassioned editorial in The Revolution.

Though Anthony and Stanton campaigned tirelessly on behalf of Vaughn, their arguments for her virtue were met with scorn. Soon, angry letters to the editor began to paint women’s rights activists as supporters not just of one desperate woman who had accidentally killed her infant, but as advocates for abortion, a major 19th-century taboo.

Then, things got even worse for the activists. Though it seemed that Pennsylvania’s governor John W. Geary might have sympathy for Vaughn’s case, the public began to accuse Stanton, Anthony and others of interfering with the legal system. They also claimed that the women didn’t care about the merits of Vaughn’s case, but were instead using her as an excuse to give women places on trial juries.

“Women will gain nothing by being tried by women,” read an unsigned 1868 editorial in the New York Times about the Vaughn case. “Man’s judgments of women have been more merciful than woman’s judgments of women.”

As a result of the WWA campaign, Vaughn was pardoned by the governor and released from prison. It should have been a victory for the suffragists, but by then the case had generated so much negative publicity for Stanton and Anthony that they downplayed their win, celebrating the victory in private and secretly funding Vaughn’s return to England (other sources say she was deported).

A few months later, the New York Times reported that Vaughn was sick, destitute and in need of funds. It’s still unclear if she was a victim or a perpetrator. Though her champions helped win her release, they were unable to solve the problems faced by a poor woman in the 19th century. But Vaughn’s infanticide trial became the spark for a discussion about the very morality of a legal system that seemed to punish women who were victims—a conversation that continues to this day.