The much-anticipated series finale of “Mare of Easttown” arrives Sunday concluding six weeks of murder-mystery intrigue and drama.

Filmed in Chester County, Delaware County and Philadelphia and set in a fictionalized version of Easttown, Chester County, the HBO series has followed Detective Mare Sheehan as she seeks to solve a murder and two missing persons cases while navigating many family struggles and dual love interests in her personal life.

Kate Winslet has earned rave reviews from fans for her portrayal of Mare — including for the detective’s on-point Delco accent.

The show has resonated among local viewers not just for its performances and compelling storylines, but also for it’s cultural and geographic references to the Philly region. Wawa, cheesesteaks, the Jersey Shore, and Cheez Whiz and nods to fans of the city’s sports teams are among those highlighted throughout the series.

And like other whodunit shows, much remains unknown headed into the last episode. The “Mare of Easttown” series finale premieres 10 p.m. Sunday on HBO and HBO Max. Here are seven burning questions that need to be answered before that episode ends.

(WARNING: The rest of this article contains spoilers from the first six episodes of “Mare of Easttown.” Only continue reading if you are caught up on the series.)

Who killed Erin McMenamin?

This is certainly the most pressing and most obvious question that needs to be answered in the series finale. 

Heading into this Sunday’s episode, it looks like Billy Ross, Erin’s uncle, shot and killed her. We also are lead to believe Billy had an affair with Erin, purchased a heart pendant for his niece after a family reunion trip and could be the father of Erin’s son, DJ. 

In Episode 6, Billy’s father, Pat Ross, reveals that late on the night Erin was killed, Billy came home covered in blood. John Ross – Lori’s husband who she had kicked out of the house for what we are led to believe is an affair with unknown character named Sandra and subsequently has moved into his father’s house – confronts Billy about what his father saw. Billy, drunk and crying comes clean about killing Erin.

By the next morning, Billy appears resigned to turning himself in to Mare Sheehan and the Easttown police, but first, one last fishing trip with John to their dad’s spot on the Lehigh River. The episode concludes with the brothers fishing as Mare approaches. 

We are led to believe Mare thinks Billy was murdered Erin; Mare is driving the mountains to arrest Billy – case solved. But given the many twists and turns of the show, that’s just what writer Brad Ingelsby wants us to believe, isn’t it?

Let’s remember just how many characters in the series have been suspects, or at least directly questioned, in connection with Erin’s death.

Dylan Hinchey, Erin’s ex-boyfriend, and Brianna Delrasso, Dylan’s current girlfriend, were established as the first suspects back in Episode 1. They were the obvious choices: Dylan is believed to be the father of Erin’s son when the show starts, and he’s shirking his parental responsibilities in favor of hanging out with his jealous new girlfriend, Brianna.

But the particularly damning evidence against them is that they are among the last people to see Erin alive when Brianna beats her up, as Dylan watches, during the party in the woods. Video of the assault is posted online for all to see.

Erin’s father, Kenny McMenamin, shoots Dylan because he believes the teen killed his daughter, but the bullet only injures him. A paternity test later reveals Dylan is not DJ’s biological father. 

A paternity test also gets Frank Sheehan, Mare’s ex-husband, off the hook after he becomes a focus of the investigation. Mare had learned Erin confided in her best friend, Jess Riley, that Frank is father of Erin’s son. Frank, who taught Erin in school, admits to helping buy her baby items, but denies any sexual relationship or role in her death, and is proven to be telling the truth, so far.

The evidence implicating Deacon Mark Burton is peppered throughout the series. He was the last person Erin called on the night she died. Burton explains that he had provided Erin with counseling, but did not tell police he had Erin’s bike, which he tossed into the creek as the investigation ramped up.

Compounding the deacon’s suspicious situation, we know Burton had been transferred from another parish after allegations of inappropriate behavior with an underage girl, sparking even more questions about the nature of his relationship with Erin.

Deacon Mark is charged with evidence tampering for trying to dispose of the bike, and he has admitted to Mare that he picked up Erin on the night of her death and drove her to the woods. But the deacon denies killing her.

There’s even a moment Mare’s daughter, Siobhan Sheehan, looks like she could be implicated after being spotted in the video of Brianna Delrasso assaulting Erin. Siobhan is questioned by Detective Colin Zabel, who believes her explanation that she had been trying to help Erin.

This all goes to show, that while it looks like Billy – and possibly John – have connections to Erin’s murder, there have been enough misdirections in “Mare of Easttown” so far to keep us somewhat skeptical. It’s hard to believe, at this point, that Billy is the only one involved.

Will John kill Billy during their last fishing trip?

Speculation that the husband of Mare’s best friend, Lori Ross, may know the details of – or be involved in – Erin McMenamin’s murder was fueled by Episode 6. 

The possibility of John Ross as a suspect really never arises during the first five episodes. Sure, Jess Riley and her mom show up at Lori and John’s house with the information that Dylan is really DJ’s father rather than going to tell the police. That connection hasn’t been explained yet, other than maybe John is the only family Kenny and Erin McMenamin have in Easttown.

In Episode 5, Lori kicks John out of the house. Lori believes – and we are led to believe – that John has been caught cheating on her again. John is back at the house temporarily in Episode 6 and he tells Lori that Billy murdered Erin. 

“We’ve got to do everything we can to keep this from Mare,” John tells Lori “Can you do that? Can you do that for our family?”

A a couple scenes later, Mare’s investigation into Erin’s heart pendant and Ross family reunion trip brings her back to Lori, who tells Mare what John has said. She also offers info that we don’t hear John say: that Billy is the father of Erin’s son and that Erin had threatened to start telling people in the town.

In light of the possibility that John is having an affair again, and that Mare is her best friend, it’s not surprising Lori opens up to Mare. But could there be something more here?

As the two brothers head out on their fishing trip, we see Billy find the gun in John’s tackle box. Why did John have a gun? Is he planning to kill Billy to protect the family name about which seems so concerned? And with Billy holding the tackle box, is he hoping the turn the tables?

We’re sure to get to the bottom of this Sunday, and it’s hard to imagine that John is completely innocent.

If Dylan didn’t kill Erin, why did he burn her journals?

Here’s where Dylan Hinchey isn’t out of the woods yet, pun intended. 

In Episode 5, we find out that after the party, the night Erin was killed, Brianna and Dylan went to bed together and when Brianna woke up, Dylan was not there. Brianna goes to the police with the information. Dylan is then brought in for additional questioning and told by Mare that he is the prime suspect in the investigation. Where did he go?

Even more suspicious, earlier Dylan meets with Jess Riley to find and burn Erin’s journals. But why? 

In the timeline of the show, that scene takes place before Billy confesses to killing Erin. It was understandable to assume then something had been written that could implicate Dylan, and he doesn’t want the police to find it. Dylan is adamant that no one read the journals before they are destroyed – does he know what is written in them or does he just not want to find out.

After Billy Ross’ confession in Episode 6, Dylan looks like a paranoid teen trying to cover tracks that don’t exist. Or maybe we’re heading towards a scenario where John, Billy and Dylan are all somehow involved in what happened to Erin.

What did Jess Riley find in Erin’s journal?

Jess Riley is present when Dylan and his friend go to Erin’s house and burn the journals – Jess in the one who tells them where they are hidden. While Dylan and the friend are feeding Erin’s secret writings into the fireplace, Jess slides what looks to be a photograph, stuck between pages of one journal, into her pocket.

Jess ultimately tells the police chief about the journals being destroyed and hands over that secret photograph. When Dylan finds out he chases her down and threatens her with a gun pointed in her face.

Perhaps more evidence Dylan had a real motive to prevent anyone from seeing what Erin had written? Maybe. But again the answer would appear more complicated than Erin writing that she had feared for her life because of Dylan.

During Sunday’s finale, we hopefully will get to find out what that photo shows.

Who will get custody of Drew?

Another tense storyline throughout the series is the brewing custody battle for Mare’s grandson, Drew.

Drew has lived his whole life at Mare’s house. His father, Mare’s son Kevin, committed suicide, and his mother Carrie is recovering from drug addiction.

Now out of rehab, Carrie is seeking legal custody of her son. At first Mare is intent on preventing that from happening, going as far as to plant heroin she stole from her police department’s evidence room in Carrie’s car. The move backfires and Mare is put on administrative leave.

In Episode 6, we have a momentary scare when Carrie falls asleep with Drew in the bathtub. Carrie wakes up to find Drew facedown in the water, but the boy was OK and just holding his breath the whole time.

Carrie’s past is dark, but from watching the show, it’s clear that she’s trying to do right by her late boyfriend. She truly cares about Drew and his well-being, and she seems committed to turning her life around, while understandably overwhelmed at times.

Momentum seems to be heading in the direction that Carrie will get custody of Drew, but hopefully the resolution of Drew’s custody will help bring Mare and Carrie closer together rather than push them further apart.

Will Siobhan leave Easttown and go to Berkeley?

Siobhan Sheehan deals with a lot. We learned in Episode 6 that she was the family member who first found her brother Kevin dead after Mare unknowingly asked her to check on him when he unexpectedly showed up at home.

The video project Siobhan is working on for school reveals she has unanswered questions about his death, and her substance-fueled meltdown in Episode 6 shows she continues to grapple with feelings regarding the discovery of Kevin’s suicide.

Siobhan also serves as an intermediary between her bickering divorced parents, Mare and Frank, and is a part-time caregiver for Drew, which she seems happy to do. All of this while apparently applying for college.

Siobhan is presented with the opportunity to escape Easttown and all of its small-town drama by attending the University of California, Berkeley. Anne, Siobhan’s girlfriend at Haverford College, is encouraging Siobhan to pursue the opportunity, even if it means leaving her behind in Pennsylvania.

“Things don’t have to last forever to matter,” Annes tells Siobhan. “I can’t be the reason you stay.”

Back in her room, Siobhan clearly is still thinking about Anne’s comment. We see her reach past an unopened letter from Berkeley to get an edible from inside a tin. She leaves Anne several voicemails, drinks some alcohol and then sends a string unanswered texts. Her college decision and evaluating the meaning of her relationship may be pushing her to the edge.

Siobhan’s future is a small plot line in the grand scheme of “Mare of Easttown” but here’s hoping Episode 7 brings some conclusion.

What is the future for Mare and Richard’s relationship?

A character who has been enjoyable to watch throughout the series has been Richard Ryan, the creative writing professor and author who moves to Easttown.

Mare and Richard met at a local bar during the show’s first episode. Since then, the two have gone on a couple dates, but have yet to start officially dating. Could that finally happen in Sunday’s finale?

It’s obvious from the moment they meet that Richard is really into Mare, who constantly appears more occupied with trying to solve the murder case than dealing with issues in her personal life, like finding new romantic partner. 

Even hearing that Mare turned down a date with him on his birthday to go out for dinner with Detective Colin Zabel doesn’t stop Richard in his pursuit. After Mare tells Richard in Episode 6 that she isn’t in a position to date right now, Richard keeps the door open, telling Mare to call him whenever she is ready. Will Mare be ready by the end of Sunday’s finale?

Mare appears on a path to peace and happiness, professionally and personally, albeit at the very beginning of the trip. Maybe the stars are aligned for her and Richard – assuming Richard isn’t Erin McMenamin’s murderer.