Mare of Easttown: Checking in With the Most Popular Theories About Who Killed Erin

HBO's new miniseries Mare of Easttown is shaping up to be quite a captivating mystery. The Kate Winslet-led thriller-drama whodunnit centers on Winslet's titular Mare, a hard-boiled detective who, on top of grappling with her personal loss and grief, is running around in circles trying to solve a year-long missing person's case of Katie Bailey – the daughter of her former high school friend and basketball teammate – only to be met with a dead end and another dead body.

Set in a small town of Pennsylvania, where everybody knows every single resident or is somehow related to them, the case gains momentum when a different murder and another disappearance follow. We've ventured more than halfway through this seven-part series, and with each subsequent episode, we have only racked up more potential suspects on our could-be list, instead of crossing enough off to whittle it down and get the full picture.

As a crime-based mystery junkie myself, I love a tough challenge that gives me ample opportunity to put my sleuth skills to use, and if you're awaiting the next episode with bated breath, chances are you do too. So bust out your note board, thread spool(s) and pins, and join us as we dissect our top theories to figure out the real murderer of Erin McMenamin ahead.

01
Dylan ​Hinchey
HBO

Dylan ​Hinchey

Erin's ex and the father of her baby, Dylan Hinchey isn't all too happy with her having baby DJ to begin with. They share the custody and he's clearly not thrilled with the prospect of sharing the responsibility of a kid – financial and otherwise. He's one of the few people to see Erin before the murder, and since we now know that he isn't the biological father of DJ, he had a plausible motive to commit the crime. As seen in the preview of episode five, he, Jess, and an unknown third person are apparently harboring a secret that might tie into the murder of Erin. Needless to say, he's a strong contender to arouse our suspicions.

02
Kenny McMenamin
HBO

Kenny McMenamin

Kenny is an emotionally distant, bad-tempered drunkard who definitely doesn't effuse warmth when it comes to his daughter and her son. While his initial reaction to finding out about his daughter's death should cross him off of this list, his impetuous action of shooting Dylan to make him pay for it doesn't scream a stable state of mind, nor strong decision-making skills, for that matter. Lest not forget, he's the only one among the primary suspects to have a licensed gun to his name.

03
Richard Ryan
HBO

Richard Ryan

The fairly new-to-town author-turned-professor Richard Ryan (played by Guy Pearce) has been pretty unproblematic till now. Apart from being a smooth-talking, promising romantic interest for Mare, he hasn't been hinted to be linked with any of the criminal affairs of the town. But could it be that he befriended Mare just to gain her trust and be in the loop about the ongoing investigation to steer clear of any roadblocks in his way? It's always the charming ones that turn out to be complete sociopaths, I tell you! Mindy Kaling seems to think so.

Another interesting fan theory postulates that, if true, this could be Richard's way to break free of the writer's block he's experiencing and create a storyline for his future novel himself. It may be far-fetched, but I'm sold on this idea.

A Reddit user even picked up on a clue in the preview that backs this theory. Tell me the guy in this screenshot doesn't look like Richard? I have my eyes on him is all I'm saying.

04
Deacon Mark Burton
HBO

Deacon Mark Burton

Deacon Mark – the priest at St. Michael's Parish – has been cloaked in enigma and, thus far, fits the bill to have had a hand in the murder. He was the last person to have talked to Erin on her cell phone, and the circumstances of his transference from his last church raise a red flag as well. He was accused (and later cleared) of being involved in inappropriate sexual misconduct with a 14-year old girl. At the end of episode three, we also see him dump Erin's bicycle in a secluded lake in the middle of the night, which police have been looking out for since the beginning of the investigation.

However, as often is the case, the lead suspect we are supposed to believe to be the culprit does not necessarily turn out to be the actual perpetrator. So, it is my guess that Deacon has either aided the real criminal or he's been sitting on the crucial piece of the puzzle box of this show.

05
Frank Sheehan
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Frank Sheehan

Mare's ex-husband Frank Sheehan was out celebrating his engagement on the night of the murder. As Erin's best friend Jess seems to believe him to be DJ's biological father, his character is called into question. While he admits to having an acquaintance with Erin, who was her student in high school, his DNA results clear him from being DJ's father. It potentially lets him off the hook without any further knowledge of his involvement that could translate into a sturdy motive to go through with the murder.

06
Father Dan Hastings
HBO

Father Dan Hastings

Mare's Manhattan-chugging cousin Father Dan Hastings is another holy figure we witness in this town. Much more laid-back and seemingly above suspicion, Dan is, again, far from having any complicity in the matter. Yet, I can't seem to fully rule him out as a possible suspect in covering up for Deacon Mark. We'll just have to wait and see how it plays out in the next couple of episodes.

07
John and Billy Ross
HBO

John and Billy Ross

Kenny's cousins John and Billy seem to be supportive and empathizing with Kenny when they first heard about Erin being gone. While on paper only Kenny owns a firearm, the glimpse of episode 5 shows that Billy may have one as well. Is it the one that was used to fire on Erin? We'll finally know more about that in the upcoming episode.

08
Brianna
HBO

Brianna

Dylan's current girlfriend Brianna isn't, um, a very nice person, to put it mildly. In the pilot episode, she not only seems to be verbally abusing and intimidatingly bullying Erin, but she also catfishes Erin into thinking that she was a genuine date for her. After luring Erin into the woods, she brutally beats Erin out, all while her gang – including Dylan – cheeringly laughed and filmed the whole debacle. Given the documented evidence, she's currently in police custody for her violent tendencies toward Erin. Although, it seems unlikely that she would create the whole scene and attract all the attention to herself right before, if she were planning at all, killing Erin. So far, we haven't had enough signs of her being the culprit. Let's put a pin in her name till then, shall we?

09
Jess
HBO

Jess

Erin's best friend Jess seems to be privy to all of her secrets, including her love and personal life. While she's shaken to her core at having lost her friend, she's ever so hesitant to disclose all the information she may hold regarding the case. She eventually opens up about Dylan not being the real father and Erin's plans to make money off registering an account on the escort website under a pseudonym to pay for her son's ear surgery. Even now, it's visible in her eyes and her body language that she knows more than she's letting on. But the odds of her killing her friend are pretty slim.

10
Freddie Hanlon
HBO

Freddie Hanlon

Another one of Mare's high school friends, Beth's brother Freddie has an opioid addiction. To support his habit, he's stolen from his sister numerous times and even gone as far as to catfish Katie's mother Dawn by falsely pretending to be the one holding Katie captive and asking for ransom. While I doubt he would've been able to execute it all flawlessly given his physical state, he might've seen something that could be important to the investigation.

11
The Father of DJ
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The Father of DJ

The biological father of DJ is yet to be uncovered. Whoever this person is either doesn't know it himself or wasn't ready for the world to find out about the news. What if he's been employing threatening or blackmailing tactics of some sort to keep Erin from disclosing the truth and, when she resisted, killed her in a fit of rage?

Also, the pendant Mare found in Erin's bedroom with the date "May 29, 2017" carved on it could lead to the father. Now, I don't know the exact timeline of the death of Kevin (Mare's son), but could he be the father? (Not the killer, obviously.)

12
The “Ferret-Looking” Peeping Tom
HBO

The “Ferret-Looking” Peeping Tom

The show opens with Mare getting a call from one of the town's elderly members, Mrs. Carroll, who informs her of a creepy prowler lurking outside their house. While it may seem like nothing at first glance, we see Mare passing by an anonymous male suspect later in the episode, who perfectly fits the earlier description. With the fourth episode indicating an active sex-trafficking ring in Easttown, it is a possibility that the Peeping Tom is none other than the van-driving kidnapper who's been picking up women – Katie Bailey and Missy Sager (that we know of).

13
Someone We Haven’t Yet Met
HBO

Someone We Haven’t Yet Met

Unless Mare of Easttown plans on pulling the red-herring-driven storyline stunt like The Undoing, the real criminal isn't the one we're led to believe, and neither are they someone outside of the world we've seen. If the showrunners aren't readying another character to be introduced into the mix in the next two episodes, chances are we know the perpetrator. I have high hopes from this show, so let's see if the writers have a few tricks up their sleeves that they use to build up to a rewarding climax. Either way, I'm too invested to back out now.