If you've been watching Mare of Easttown on HBO, there's a good chance you look something like this right now:
We're only four episodes in, and it seems like for every answer we get, two new questions pop up.
For the sake of theorizing, here are all the people we've been introduced to who could be the killer:
1. Frank Sheehan
2. Dylan Hinchey
3. Brianna Del Rasso
4. Dylan's parents (either one of them)
5. Kenny, Erin's dad
6. Father Dan Hastings
7. Faye
8. Helen
9. John Ross
10. Erin herself
11. Richard Ryan
12. Officer Trammel
13. Deacon Mark
14. The guy who kidnapped Katie and Missy
15. Any combination of two or more characters
16. Some other random person
The following people are technically still suspects, but I think it's highly unlikely that they had anything to do with Erin's death:
This is purely speculative, and I may eat my words later.