Biggest problems with Dexter as a suspect
Am I alone in both Angela's and Kurt's accusations are incredibly weak?
Kurt was absolutely wasted and what, noticed dexter coming from the direction of the fire/smokestack that was emitting ash, not snow? That's a lot to make that jump to "You were clearly disposing of my son's body." Now yeah, he found the pin, but it's a stretch to go as far as to kill Harrison and Dexter because of that. Granted, I don't know the layout of the town, perhaps if that direction ONLY went to the fire/smokestack, otherwise it's not enough.
Angela get's a hand written letter in her mailbox and decides her boyfriend killed Matt? The framing story was significantly more likely, particularly given that Kurt looks to have skipped town AND clearly burned down Dexter's house.
Lastly, when Angela is talking to Bautista she says "We have some cases similar to the Bay Harbor Butcher." What? Based on the needle incision mark alone? The bay harbor butcher chopped his victims up into little pieces, he kept blood slides, there's neither of this for these victims. I think she implies the Ketamine is a link, was it ever confirmed that's what Dexter used in the OG series? He always says horse tranquilizer, so maybe it is?