Every Remaining Murder Suspect in 'Mare of Easttown'

The first episode of the HBO limited series Mare of Easttown ended with a gruesome image: a naked woman with a bullet hole above her eye, dead in a river basin. Murder! By the shocking end of Episode 6, we seem to have a confession from one of the suspects, but can you trust it? Not really, since there are still a lot of unanswered questions, and the episode's final scene reveal promises to change the trajectory of the hunt.

The question of who killed Erin McMenamin (Cailee Spaeny), the murdered teen with an surgery-needing infant named DJ, a notably antagonistic ex-boyfriend named Dylan (Jack Mulhern), and a now incarcerated father named Kenny (Patrick Murney), is still an open question, not to mention the matters of why she was killed and how. Yes, despite Billy Ross (Robbie Tann) having seemingly fessed up to killing her, that scene with John in Episode 6 and subsequent discussions between John and Lori and then Lori and Mare essentially amount to hearsay. In other words, the show has a few potentially viable suspects still in play heading into the finale.

The first five episodes of Mare of Easttown dig into Erin's past while Detective Mare Sheehan (Kate Winslet) also juggles an investigation into two missing-girl cases that were initially thought might be connected with the murder but are revealed not likely to be in Episode 5. After the major revelations in Episode 6, there's only one episode to go, and Mare has redoubled her efforts to solve Erin's murder. Let's investigate along with her, and parse the viable killers and the likely red herrings, which we'll list here in order from prime suspect(s) to the technically still possible.

Why it might be him: Right now, it sure looks like Billy killed Erin, since we heard him say as much in Episode 6. After their father, Pat, tells John that Billy came home very late on the night of the murder covered in blood, John confronts Billy about it and coaxes a confession out of his brother. Later, Lori tells Mare that John had told him that Billy had started up a relationship with Erin, his niece, at a Ross family reunion weekend back in 2017, and says that Billy is the father of Erin's baby, DJ. There's also the receipt in his name for the 5-29-17 necklace that Mare uncovers. Slam dunk that it's Billy, right?
Why it might not be him: Not so fast. There are still holes in this narrative—namely, that John could be pressuring Billy to say he acted alone, which might make sense if John himself or one of his family members was also somehow involved in Erin's death or DJ's parentage. The scene between them picks up mid-conversation and could be read as John pressuring Billy to take the fall for him. John is also pushing Lori not to tell Mare about what Billy had confessed to, in order to protect their two children, Ryan and Moira. Mare, whose investigation had already led to Billy's likely involvement, believes her best friend, but why did Lori wait until Mare asked about it directly? And is she telling the full truth or following John's plea to hide information from the police in order to save her family? Given that he discovered a gun in John's tackle box, Billy may now suspect that John wants to frame him, with Lori's help spinning a false narrative to Mare, and stage his death as a suicide. And the necklace might be a misdirect. Regardless, the case on Billy is not open and shut.
Our final prediction: Billy helped move Erin's body at John's request, but he played no part in his niece's death and isn't DJ's father.

Why it might be him: The winner of Mare of Easttown's "most sus" award goes to John Ross. As Mare herself says in Episode 1, John's a horrible liar. Vanity Fair's Joanna Robinson laid out a very convincing theory that John is the obvious killer, and Episode 6 only bolstered that interpretation. Regardless, we know something is up with John, and it's more and more clear that he's fully in control, or at least heavily influencing, the narrative around his family's likely involvement in or knowledge about Erin's death and DJ's parentage. He's coaxing his son, Ryan (Cameron Mann), into keeping quiet about something, and then, after Ryan lets the secret slip to Lori that his dad has been seeing the same woman he'd been involved with in the past, John uses protecting the family as a way to convince his wife to withhold crucial information from Mare. Lori tells Mare that John has been having another affair with someone named Sandra, but then acts evasively a few scenes later when she thinks Mare's going to ask more questions about her marital problems. She only discloses the Billy bombshell once Mare brings it up. It's also definitely possible that John is feeding false information to Ryan and Lori to deflect their and Mare's attention away from an even darker family secret, namely, that John is the one who engaged in incestuous relations with Erin and is DJ's father. If you watch every episode with this in mind, much of John and Lori's behavior, as well as the reactions of Ryan, Billy and Kenny, makes more sense. In terms of motive, Erin may have threatened to reveal all of this to Lori or the police unless he paid for DJ's ear surgery.
Why it might not be him: Too easy! It might also not qualify as a big reveal at this point, given that Mare is headed to confront Billy and John right now, although Lori's potential involvement at least in a cover-up would make it more shocking. There's also plenty of murky behavior on many other characters' parts as well that doesn't exactly exonerate them, and we still don't know who's in that photo. So maybe John's acting the way he is out of extreme self-preservation and to protect his family, in the event that Billy did in fact kill Erin. And it's still technically possible that an affair with Sandra (who we haven't met yet) is what he's hiding. Another theory floating around is that he's Erin's biological father and that's the secret he asked Ryan to keep.
Our final prediction: Yeah, OK, John Ross totally did it. And that has to be him in the photograph, right?

Why it might be him: Dylan, who it turns out is not the biological father of Erin's baby, has only behaved more suspiciously as time has gone on, and he started out pretty suspicious. Not only did he stand by idly while his new girlfriend, Brianna, spat jealous accusations and punches at Erin, his attitude toward his ex comes off as straight-up insidious. He even refused to help pay for DJ's much-needed ear surgery back when he thought he was the father! He gets even more suspicious in Episode 5 when Brianna reveals that she woke up at 2am on the night of the murder and he wasn't anywhere to be found, then he goes on a little journal burning expedition, throwing all of Erin's diaries into a fire, and follows that up by threatening Erin's friend Jess (Ruby Cruz) with a gun if she dares to reveal anything further to the police. What's this guy hiding?
Why it might not be him: For a show as densely plotted as Mare of Easttown, having the ex be the murderer would be too simple without some sort of misdirection, so we're going to say... it's probably not going to be him. He also seemed genuinely surprised to learn that DJ wasn't his biological son, and also genuinely seems to like being DJ's dad, so rule those out as motives. His behavior seems to be more in line with keeping a lid on something personal or legally damaging (e.g., drug-dealing) that Erin may have known about and may have put in her journals than anything having to do with her death.
Our final prediction: If he had anything to do with the mystery surrounding Erin, it's that he may have witnessed the crime or somehow been involved in a scuffle that inadvertently caused her death, but more likely he wasn't involved at all and is just acting belligerently because he's in self-preservation mode (and a total jerk).

Why it might be her: OK, hear me out: Lori, Mare's best friend, killed Erin to protect her family after Erin threatens to go to the police about John having raped and impregnated her at the family reunion. If that cockamamie theory seems too unlikely, would you go for another wild theory that it was, in fact, Ryan who killed Erin, and she's abetting the cover-up to save his reputation? Also consider that she left the bar early and had the opportunity to commit the crime or help someone cover up the crime. Plus, Erin's dead body was placed in the same pose as the figure on the back of Lori's Dave Matthews Band T-shirt.
Why it might not be her: She went home early and stone cold sober (she was the designated driver) to take care of Ryan and Moira so that John could go to the bar after Frank's party. The T-shirt death pose is likely a writerly contrivance that allows the show to play around with the idea of things happening behind our backs (or in Mare's case, in our backyard, as Frank, another suspect, lives in the house right behind hers, or under our noses, if it's her Siobhan). She'd have more of an incentive to have killed Erin if Ryan is in some way involved, but the show won't go in that direction, will it?
Our final prediction: Lori didn't kill Erin and doesn't know anything truthful about what happened to Erin, at least not for most of the season. Everything she "knows" seems to be a narrative full of half-truths and self-serving obfucations fed to her by John, the likely actual culprit. If she's guilty of anything, it's purposefully lying to Mare in Episode 6 about Billy at the behest of John, but without knowing the real story. Either way, learning that Lori hasn't been honest with her about something as important as a murder would be devastating for Mare.

Why it might be him: Deacon Mark Burton is in custody going into the finale, albeit not because there's strong evidence against him, but because he hasn't been forthcoming with the police. Accused of raping an underage girl at his previous parish, he first admitted that Erin had called him the night of her murder, later changed his story to having picked her up from the woods party, and then finally admitted to having disposed of her bike after dropping her off at the park where she was killed. Very suspicious behavior!
Why it might not be him: First, viewers would roundly boo such a tropey outcome. And while he doesn't have an alibi, his admission to Father Dan about why he's withheld crucial evidence makes a lot of sense: He lied about his interaction with Erin because the circumstances of his transfer to Easttown and the bike in his car would have instantly made him the prime suspect.
Our final prediction: He's the only suspect who seems to be telling the 100 percent truth. He'll be getting out of jail soon.

Why it might be him: What is the deal with Richard Ryan, a creepy serial killer name if we've ever heard one? He's the only outsider in the premiere episode, which makes him a suspect by default. Mare meets him at the bar, where he explains that he's the author of a successful book from the 1990s and that he moved to the Philadelphia area a few months back from Syracuse to guest-lecture at a local college. They hit it off and end up sleeping together, so maybe he's going to serve as a plot device to shake up Mare's life, but maybe he's secretly researching his next book by also committing the murders he'll be writing about? He was with Mare that night, an alibi as sturdy as they come, but what happened after Mare went home? Also Guy Pearce is one of the most famous people on the show. Is this really all he's going to do?
Why it might not be him: He was with Mare the night of the murder, an alibi as sturdy as they come.
Our final prediction: Richard is absolutely not guilty—unless the twist is so outlandish that we veer into Lifetime Movie territory. He seems like the real, if slightly unbelievable article, the handsome out-of-towner who helps Mare finally move past the problems that have rooted her in place and offers her a future. Bonus proof: Pearce wasn't originally cast in the part; he took it on as a favor to Winslet when production delays forced the departure of the less famous original actor (Ben Miles).

Why it might be him: John and Lori's son is clearly going through it. He wails on a lunchroom bully who flings food at his sister, and breaks down following the incident as his mother asks him if his father is "doing it again" and if it's "with the same woman." He has been groomed by his dad to keep secrets from his mother, and if he somehow learned that his dad was being blackmailed by his cousin Erin, perhaps he cracked after coming back from Frank's party, left home in the middle of the night despite not having an easy way of getting to the park, somehow found the right kind of gun, and shot Erin and made it home without anyone noticing.
Why it might not be him: His behavior seems more indicative of how fiercely protective he is of his family members, and due to built-up stress from having to keep a dark secret, not of how violent he is. This is a good kid, one who proactively does his homework on a Friday night, who learns something awful and is struggling to process it.
Our final prediction: Our boldest prediction that is also the least likely to be true: Ryan was doing his homework early because he had to get up early... to look into more of his neighbors' houses. Yes, Ryan is the legendary ferret-looking peeping Tom who spied on Betty Carroll's granddaughter that Mare drew a sketch of in the very first episode, and his secret noctural habit will inadvertently spur the seemingly unrelated technological upgrade—the activation by Mr. Carroll of the security cam on the day of Erin's murder—that will help Mare discover a crucial clue in the investigation.

Why it might be him: Mare's ex-husband, Frank, held his engagement party on the night Erin died, and most of his and Mare's family members and friends were in attendance, so he would seem to have a solid alibi. However, the weirdly raucous suburban bash (a live band performed! multiple 40-somethings got mega-wasted despite kids and a priest being involved!) had broken up by the time Erin walked into the woods, which we know because Siobhan and her bandmates had just arrived at the outdoor gathering during her beatdown by Brianna, and Frank (and John) had turned up at the bar where Mare was drinking with Richard after the high school basketball championship anniversary ceremony. Could he have snuck away long enough to have committed the murder? Conceivably. He did, of course, lie to Mare about how well he knew Erin, and that's something he hasn't adequately explained. But what's the motive? A DNA test already exonerated him from paternity. Maybe Erin threatened to tell fiancée Faye that Frank was the father of DJ if he didn't cough up cash? Is there a reason Faye moved out?
Why it might not be him: A DNA test ruled him out as the father of DJ. He was surrounded by friends and family members all night. He woke up super-early to go to church and take care of his grandson.
Our final prediction: Pam's ex from The Office is not Erin's killer and not the father of DJ. But Frank may know more than he's letting on. Don't rule out that one of his friends (e.g. John) or relatives (Kevin?) might turn out to be DJ's dad, but it would be a truly strange revelation at this point if it's revealed that he killed Erin or had anything to do with it. Far more likely, Frank will figure in to Kevin's backstory in a bigger way than we currently know about as Mare continues to be challenged to remember the events that led to their son's suicide.

Why it might be him: Erin's dad is full of rage, disappointment, and resentment, and, quite frequently, a ton of alcohol. He also doesn't have an alibi. Could he have blacked out and killed Erin on an epic bender? Maybe. And just because he's in jail for the attempted murder of Dylan, a crime he freely admitted to, doesn't mean he didn't also kill his daughter.
Why it might not be him: There's zero motive, for one thing, that we know of. His anger manifests more as frustration with his lot in life and it's largely directed at Dylan, not Erin. Gunning down another teen certainly implies he has the capability to kill, but targeting Dylan out of sorrow and anger seems to indicate that he didn't actually kill his daughter. If he did, why would he want another prime suspect dead?
Our final prediction: Kenny's grief reads as entirely genuine. He had nothing to do with Erin's death, but we wouldn't be surprised if he hasn't disclosed everything he knows about Erin's past and how his cousins may have figured into it.

Why it might be her: Could this crime hit close to home? As one of the last people to see Erin alive, and her still unexplained absence from the Sheehan household all the next day, Mare's daughter, at minimum, had the opportunity to commit the crime. While we have yet to be shown anything that would explain what would lead Siobhan to murder Erin, she is producing a documentary about her brother, Kevin. Maybe she discovered a link with Erin that somehow worsened Kevin's depression? Or maybe Erin blackmailed her with a threat of telling the police that Frank is the father of DJ (even if it wasn't true)? 
Why it might not be her: Mare's daughter stepped in to stop Brianna's beatdown out and then offered Erin a ride home out of genuine concern. Her storyline may instead indicate that the killer and/or the father of Erin's baby may be someone close to Mare. It also serves as a way to explore Mare's unresolved grief over her son's death, as Siobhan's anger toward her mom is centered around Mare having sent her to check on Kevin on the day he committed suicide.
Our final prediction: Siobhan is a nice girl who really wants to see boygenius and reconnect with her family. There is nothing more to her story than that.

Who else could have feasibly killed Erin? A short list of potential, viable candidates still would have to include: biggest enemy Brianna Delrasso (Mackenzie Lansing), best friend Jess (Ruby Cruz), kinda creepy Father Dan Hastings (Neal Huff), and some absolute random or unrelated event (stray bullet fired by, say, Glenn Carroll at a peeping Tom that somehow richochets its way to hitting Erin), and her death is more of a McGuffin to examine the various personae of Easttown. And lest you think we have forgetten Helen Fahey (Jean Smart), Mare's mother, what kind of smacked-ass do you think we are? But she's too interested in playing Fruit Ninja to care enough to murder anyone.

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