Following on from Jeffrey Dahmer, the Menendez brothers and Ed Gein, Netflix’s Monster has gone further back in time for its fourth installment, focusing on one of America’s most infamous unsolved true crime cases.

In August 1892, Lizzie’s father and stepmother, Andrew and Abby Borden, were brutally killed at their home in Fall River, Massachusetts, with a hatchet. Although suspicions fell on Lizzie and she was tried, due to a lack of evidence, she was acquitted – and no one was ever charged.

Bridget – or Maggie, as she was known by Lizzie and her sister Emma – was a 26-year-old Irish immigrant who had worked as the Borden family’s live-in maid for nearly three years by the time of the murders.

Other than Lizzie, she was the only person known to have been at the property when the crimes took place, and she gave crucial testimony during the trial. As far as the historical record shows, Bridget and Lizzie’s relationship was simply that of a domestic worker and her employer.

Nearly 100 years later, however, a theory emerged that Lizzie and Bridget had secretly been lovers, something Monster explores. But there is no known evidence that the pair ever had a romantic relationship – in fact, the idea appears to have originated in Evan Hunter’s fictional 1984 novel Lizzie.

And unsurprisingly, there’s even less evidence that Bridget rocked up to the Borden house armed with a prototype wooden vibrator and dildo. But there is a deliberate reason the Netflix series gives her these items, and it’s the same reason Bridget and Lizzie are depicted as lovers.

Bridget is reimagined as the ‘catalyst’ for Lizzie’s awakening

What we know about Lizzie as fact is that she lived in the Gilded Age, a time period where women had to adhere to strict societal and sexual standards. Lizzie herself led a restricted life dictated by these standards, and this is something we see play out in Monster.

Bridget was reimagined as the antithesis of this – she’s travelled, she’s sexually liberated, she dyes and cuts her hair, and yes, she shows up with old-timey sex toys. Bridget becomes the reason for Lizzie’s awakening, allowing the show to explore themes of female rage, repression and, ultimately, what causes a person to snap.

Speaking to TV Insider, Monster co-creator Ian Brennan explained, “Bridget is really a catalyst. She’s like a foreign object that gets introduced to this ecosystem, and completely turns it on its head. I think Lizzie’s just completely perplexed [by Bridget] at first. She becomes, very quickly, an object of deep fascination and then desire.”

Bridget actor Vicky Krieps separately told Vanity Fair, “The way Ryan [Murphy] thought of it, she’s almost like a Mary Poppins that comes out of nowhere, who can be anyone from any time. Ryan said, ‘It’s women-driven, feminist, lesbian, dirty, unapologetic.’”

Or, as Abby Borden star Rebecca Hall put it, “It’s Ryan Murphy does Cinderella.” And the outlet compared Bridget to Lizzie’s Fairy Godmother: “In this warped fable, Fairy Godmother’s magic wand is an early wooden prototype of a dildo.”

“For a person who’s been so sheltered, it feels so liberating to meet someone who has a more evolved modern sensibility,” added Ella Beatty, who takes on the titular role of Lizzie.

But it’s director Max Winkler’s comments that really make sense as to why the writers depicted Bridget, and her relationship with Lizzie, in this way. She represents everything Lizzie is denied.

As he told Reuters, the unanswered questions surrounding the true crime case gave them a chance to explore the limitations placed on women during that era.

“You’re essentially treated like a piece of property, and your ​best role is to ​get married off and ⁠have as many kids as possible,” Winkler said. “Lizzie can’t get married off. She can’t find someone to take her.”

Once again, these themes allow Monster to circle back to the question at the centre of every season: are monsters born, or are they made?

“As you get to learn more about people and what ⁠the pressure ​cooker is that leads people to snap, anyone can ​kill anyone,” Winkler added. “It just is what are you willing to kill for, or what leaves you no choice, and this ​show is no different. It’s just the killers look different.”