I don't think they'll go the route of the film where the wife did it, since it would be unoriginal. I think the reveal is going to be that he did it. Guy is unstable, essentially stalked her, and there's no other evidence that points to anyone. They've thrown a whiff in some other directions and made us think that Tommy Molto is "the bad guy" out to get Sabich on some personal vendetta. They have the audience tentatively cheering for Sabich.
I think he snapped and did it. Maybe it was a manic episode and he only remembers the snippets he keeps dreaming about. And maybe he'll get acquitted. But I think that's what they'll do with the story.