Tonight’s installment of BBC One’s Dublin Murders (episode four, for those counting) dropped bombshell after bombshell after bombshell.

Firstly, the discovery of Lexie’s body left Cassie and her colleagues stunned. As they pointed out, time and time again, this isn’t just a case of stolen identity: these women could basically be twins. They look so similar, in fact, that Cassie is ordered to leave the crime scene so as not to “confuse the paramedics”. 

Later, we learn that Lexie was three months pregnant at the time of her death - a fact which prompts Cassie to take a pregnancy test herself. And it isn’t long before she’s sent reeling back into her own past, with a series of flashbacks offering up an insight into why she chose the Garda in the first place.

While the authorities search for who Lexie was, Frank and Cassie are keen to find out why she was murdered. To do this, Frank suggests that Cassie go undercover in Whitethorn House, where Lexie lived with her four best friends (all she needs to do, he reasons, is cut in a blunt fringe and literally nobody will notice that a brand-new human has moved in with them). Cassie initially resists, bristling at Frank’s suggestion that she’d be happier pretending to be someone else. However, a disastrous night with Rob soon changes her mind…

And so, just like that, the fourth episode of Dublin Murders has left us with even more questions than last night’s installment. 

Here, Stylist’s digital editor Kayleigh Dray does her best to unravel them all.

So, who was Lexie?

There’s a theory on Twitter that, when Cassie was younger, she had an imaginary friend called Lexie (see the flashback with The Shining twins for reference): blaming her more destructive tendencies on “the other little girl” helped her to deal with the untimely death of her parents.

Now, though, it seems Lexie is 100% real. Or, rather, she was 100% real: in episode three, her cold, lifeless body was found in an abandoned farmhouse. And, in episode four, her body has been cut open by forensic scientists and examined meticulously. Cassie’s not-so-imaginary pal is dead, and she was pregnant at the time of her passing. And she looks so much like Cassie, apparently, that our heroine is able to cut her hair, adopt a faint sense of amnesia, and slip into Lexie’s old life in a bid to figure out what happened to her.

In the books upon which Dublin Murders is based, Cassie becomes too intertwined in the dynamics of the house, and quickly figures out that each of Lexie’s housemates played a small part in her death. 

However, some readers were left confused about the link between Cassie and Lexie. Particularly as, y’know, “there is no Lexie. There is no Lexie. There’s just you!”

Could Lexie be an imaginary friend made real?

We have already unveiled the evidence which suggests Dublin Murders isn’t so much a detective drama, but a supernatural one. So is it that much of a stretch to suggest that Lexie’s imaginary friend has been brought to life by the same powerful forces that pervade the woods where Katy Devlin’s body was found?

Well, possibly. However, it’s worth noting that the show’s writer, Sarah Phelps, recently opened up about how the series was influenced by a real-life incident where a man suggested the fates would be disturbed if a particular tree was cut down. 

As reported by Hello, she said: “He won [his protest] because at some deep, metaphysical level every person involved [must have] woken up at 4am and thought ‘What if he’s right? What if you cut down that tree and all hell breaks loose?’”

What are people on Twitter saying about it all?

Once again, the people of Twitter are absolute baffled by the events of Dublin Murders.

Could this all be related to the ‘fetch’ of episode three?

Forget what you learned in Mean Girls: a fetch, as one savvy viewer pointed out on Twitter, is a supernatural double or apparition of a living person in Irish folklore.

It seems to be a key factor in this show’s plot: we have Cassie and Lexie, as our first set of fantastical doubles. Then, we have Rob and Adam - purportedly the same person with a new identity, but quite possibly a changeling child that was swapped in the woods back in 1985. And let’s not forget the twins at the centre of the show’s original murder plot.

Hmm.

Why was Rob so cruel to Cassie?

For a moment, it seemed like fans’ prayers had been answered: Rob and Cassie finally gave way to all of that sexual tension, and enjoyed a night of searing passion.

The next day, though, Rob was cold and indifferent. And it wasn’t long before he was telling Cassie that their evening together meant pretty much nothing to him.

“Crying girls make me hard,” he said, a smirk playing on his lips. “You know that.”

Is Rob, as many have suggested, an absolute psychopath, incapable of feeling or empathy? Or is he simply afraid of getting close to someone after building up so very many barriers?

Time will tell, we suppose. However, his attitude drove a shattered Cassie - oops, we mean Lexie - back into the world of undercover policing. 

So, who killed Katie Devlin?

Are you joking? We literally haven’t the foggiest: this week’s episode completely abandoned the Devlin murder to focus on the Lexie investigation. 

Maybe we’ll learn more next week, eh?

The next episode of Dublin Murders will air Monday 28 October, 9pm on BBC One. 

Read our episode one recap here.

Image: BBC One