7 Of The Wildest Mare Of Easttown Theories That Aren’t You-Know-Who

Spoilers ahead. As the finale looms just around the corner, HBO's Mare Of Easttown would love for us to believe that we've got the show's central mystery all figured out. It's obviously Billy Ross (Robbie Tann). He's confessed to the murder, and all Mare (Kate Winslet) needs to do is nab him.

But as we've learned from the series' last six episodes, everyone is a suspect — and many fans are convinced that the answers to who killed Erin McMenamin (Cailee Spaeny) and who fathered her child, DJ, are much less obvious that it seems. If you don't think we're in for another surprising twist, then take it from one of those said fans, acclaimed author Stephen King: "Not convinced that Billy killed Erin. I have a suspect in mind. Tellya next week if I'm right," he tweeted after the penultimate episode.

Again, nothing in Easttown is that simple, so nobody else can therefore really be trusted — or ruled out. So if it's not Billy, then who? Ahead are some of the internet's wildest theories.

Perhaps the most popular theory (and neat, if you ask us, but King disagrees), is that Billy's brother John is actually the father of Erin's child and either killed her himself, or had her killed by his brother. A known adulterer and skilled liar, he could have easily manipulated Billy to take the blame ("Say, 'I killed her," he coaches his brother in episode 6) or even to go through with Erin's murder on his behalf. Also, the receipt from the jeweler where Erin's necklace was purchased just says “Ross” and no first name, which Mare assumed meant "Billy," but could also have been "John." Another clue: Billy earlier in the same episode angrily yells to John, “You made a mess of your life because you couldn’t keep your dick in your fucking pants. Now you clean it up!” you're supposed to assume that he's referring to his brother's affair, but he could be also talking about Erin.

One Reddit user thinks it's John and Lori Ross' teenage son Ryan (sad!). The idea is that Ryan, who knew that his father was having an affair, killed Erin out of anger. "Billy is helping cover it up out of familial loyalty, and John obviously feels guilty," they wrote. The only part that's a bit fuzzy is the question of Erin's baby's father: "Who the baby daddy though? Doesn’t fit my theory so.. lol," they added.

Another theory is that Lori (Julianne Nicholson) found out about her husband John sexually abusing their niece, and contacts Erin pretending to be John to meet her at the park. Things get out of hand, and there's a confrontation, Erin brought a gun and it accidentally goes off and kills her. "Lori calls Billy to help. At some point, well after everyone first heard of Erin's murder, Lori confesses to John," another Reddit user wrote. "Finally, when Dad Ross reveals he saw bloody Billy, John decided to manipulate Billy into taking the fall to save Lori and his family. But he doesn't think Billy will hold up, so he decides to stage a self defense killing OR suicide of Billy out at the fishing cabin."

Here's a dark one: Mare's dead son, Kevin (Cody Kostro), had an affair with Erin and is DJ's father. When Mare sees him appear in her grandson Drew's room just before getting the call about Erin's death, it links the two characters in her mind. Also, the baby has red hair, and the only character in the show with red hair was Kevin. There is one issue, though. Kevin died by suicide in February 2018 and DJ was born in November 2018, so it's likely that it's not Kevin in the mysterious photo that alarms Chief Carter so much that he needs to alert Mare right away. It could be Siobhan (Angourie Rice), Mare's daughter, in the photo, as she saw Erin at the park and offered her help a few hours before she was killed. Maybe she helped keep the secret that Kevin was DJ's father? One Redditor even pointed out that in Siobhan’s movie about Kevin, she says "'The last time a heard my brother’s voice...I wonder who was with him. Was he alone?' Kevin, in this moment, is with Erin. Possibly at the family reunion at the lake (which would explain the water/beach in the video)."

Yes, Mare's ex-husband, played by David Denman, was our very first red herring earlier in the series, and was dismissed as a potential suspect via DNA test, but who's to say that he didn't kill Erin? Maybe on behalf of his late son (Kevin), the father? He did buy Erin diapers, after all. And why is his fiancée Faye still so mad at him even though he was supposedly exonerated by DNA?

There's honestly no great reason why Mare's author love interest would be involved, but a lot of viewers have been wondering why such a famous actor as Guy Pearce would be cast as such a fringe, innocuous character. Maybe he's DJ's father?

The stuff with her having an affair with the old man who died? Funny, but also could be sketchy. Honestly, it would just be great to see Jean Smart emerge as the evil mastermind behind the whole thing.