Since the show started, Deacon Mark has been an obvious suspect, especially once viewers learned he was transferred to this parish to cover up a relationship with an underage girl. But Episode 5 proved he wasn’t a violent man, and the image of him killing Erin paled in the face of his tearful confession that he took her to the place where she died.

But here’s the thing: Just because Deacon Mark isn’t the murderer doesn’t mean he’s not the baby daddy. Everything about his story suggests he was once again emotionally involved with an underage girl, if not sexually. His guilt is obvious. Either he is the baby daddy, or he knows who is.

The other significant suspect who rose to the top of the pile this week: Billy Ross. Both he and his brother John have an alibi for the night of the murder; they were out partying with Frank before taking him home. But his intensely nervous reaction when it came up that Erin had lived with him for months might as well have been a confession. Consider how he tried to play it off that it was like “a few days,” only to have Lori innocently protest that it was a few months — and right around the time she got pregnant. That was a field of red flags.

Moreover, and this is something fans have noticed since the early days of the show: DJ is a redhead. Erin and her father are not, Dylan’s not, Mark’s not... But Billy is.

One of the things fans can’t shake is the idea that whoever turns out to be the killer and/or baby daddy is going to be someone that hurts Mare. Hence why fans were so sure it was Frank when Jess raised the issue over his diaper deliveries. Mare having to arrest her ex-husband would be a new trauma she’s not ready for.

But what if it’s someone even closer than that? What if it’s her cousin, Father Dan? Fans noted that he didn’t run to the police with Deacon Mark’s confession. In fact, he seemed to be thinking real fast as the weeping Deacon sobbed at him. Is he afraid Erin told Mark the truth?

This week, Billy emerged as the new and shiny suspect of the moment. But as noted earlier, the show’s been doing that since the first episode, only to prove otherwise the following week. What if Billy’s anxiety about leaving that Rolling Rock untouched wasn’t for himself but his brother?

The latest episode made it painfully clear that Ryan knows something about his father he’s not supposed to talk about. And Lynn seemed to put it together that John was cheating, though with who, she didn’t say. What if Lynn is guessing wrong? What if John is the one who was molesting Erin the whole time she was staying at Billy’s? That would also explain the red hair — a recessive trait. It might also explain the kid’s name. Viewers assume the “D” in DJ is faux-daddy Dylan, but what’s the J for? Could it be for real-father John?

How would Lori respond if Mare had to tell her John was the father of Erin’s baby?

But perhaps the most prominent “Mare-centric” answer would be the one person who could father Erin’s baby but then not be there to kill her: Kevin.

Fans have been obsessed with the idea of Siobhan somehow being involved. After all, she was one of the last to see Erin alive. The big issue is that Siobhan can’t be the father of Erin’s child, so if the killer and baby daddy are the same people, that automatically ruled her out.

But Kevin could have been. Fans know he committed suicide, though not why. Could he have found out he had a second baby on the way, this time with an underaged girl? Could Siobhan then be the killer, keeping her brother’s name untarnished?