'Harper's Island' is running down to its last handful of episodes, and before the killer is finally revealed in the finale, I thought I better stake out my theory of who is to blame for all those deaths.
First off, I was on board with the idea that Abby was the daughter of the (presumed) dead killer John Wakefield at first. But as is the case with the present-day killer's identity, I think such a reveal would be coming too soon if that was true.
Based on this past week's episode, "Seep", I think the dialogue was worded in such a way to lead us into believing that Abby is Wakefield's daughter. But the scraps of Wakefield's journal that we saw also was worded in such a way that he never came out and said that the child Wakefield fathered with Abby's mother was actually Abby. He only kept writing about "MY child". As that stands, it may prove to be that their child together is someone else, maybe even male.
As to who the killer is, a lot of people are expecting that it will turn out to be John Wakefield himself, picking up where he left off seven years before. Apparently the pictures we've seen of Wakefield have been of an actor notable for his recent stint on the late 'Battlestar Galactica'. The thinking is that why go to all that trouble to hire such an actor if you're not going to actually have him in the show?
But I think Wakefield will prove to be a red herring. Oh, I think he's alive as well, and that he will be showing up before the end game. But he will turn out to be a diversion like the casting of Harry Hamlin as Uncle Marty had been in the first episode. We're going to finally confront Wakefield, accept him as the killer and then - THWAPT! - he's going to be dispatched just like all the others.
As for the real killer? First off, I think it has to be somebody who knows Harper's Island, and has had plenty of time to prepare before the wedding celebrants arrived on the ferry. Setting all those traps, digging that ditch in which Lucy was burned to death - that all takes time.
So I don't think it's any of the wedding celebrants who arrived on the ferry. I think it's somebody who was already living on Harper's Island.
My suspect? Nikki Bolton, the bartender at the Cannery, and an old friend of Abby's.
As to why it's her? She was introduced into the storyline early enough to establish her presence so that we can't cry foul at a late-game entry when the Big Reveal is made. And after a few key scenes of her interacting with some of the regulars, she was faded back from view. (This was probably done so that we don't focus on her too early as even a suspect, let alone as the actual killer.)
As to why she's doing it? Maybe she's the actual child of John Wakefield and Abby's mother, given up for adoption at birth. And only now she's discovered her true heritage - and having inherited her father's madness has come to accept her heritage and destiny to carry on his killing spree. And it could be that Nikki, although professing to be Abby's friend, is angry that their Mom kept Abby but not Nikki to raise as her own.
And maybe she's jealous about Abby's relationship with Jimmy. Knowing that Abby was coming back and that Jimmy never got over her (probably despite Nikki's best efforts to help him forget), it put her over the edge and ready to kill.
I also think that it may play out that when John Wakefield does finally show up, he'll be all remorseful and try to warn Abby - which is when he'll be dispatched by his own real daughter, Nikki.
Just my ideas. In the end, I'll probably be proven wrong about most of this. When it comes to my Toobworld theories, I usually am....