If, and at this early point in the show it’s still a definite ‘if’, Danny did not really kill his aunt, the only logical conclusion is to assume he is covering for someone. Here are the characters he’s most likely to have taken the fall for, and the reasons why they may or may not be so likely:
Why it’s likely: First off the fact that we see her and Lacey outside when Danny came out and confessed to the murder doesn’t mean she couldn’t have done it. He’s been inside awhile, maybe Jo and Lacey only recently started playing on the swings and five minutes ago they were inside as well. Also as someone pointed out to me, the scene we saw was Jo’s dream of the events. We already know she and Lacey have different memories of the events as they disagree on the color of the jump rope. Jo’s dream might not be a reliable account of events. Also Jo is very much someone Danny would protect at all costs.
Why it’s not likely: Danny’s conversations with Jo, especially the one’s about his aunt, would make very little sense if they both knew she was the killer. Even if she had repressed the memory, Danny wouldn’t know that and his reactions to her wouldn’t be very illogical, not even blinking an eye when she asks about his motive for the murder? Also, how could the infamous Aunt/Regain necklace really relate to Joe?
Why it’s likely: Like Jo, she could easily have committed the murder. Given the fact that the pilot showed us just a hint of possible romantic attraction between Lacy and Danny, she as the killer would add a lot of drama (though if Danny knew she was the killer, would he be likely to pursue a romantic relationship with her? Particularly given the fact that if Danny is innocent, the killer of his aunt probably killed Regina as well?). She could also have easily taken the necklace from the aunt’s body and as Regina is her friend, she could have given it to her (Regina did say it had been a gift). Lacey and Danny have yet to have any conversation that wouldn’t make much sense if they both know she killed the aunt. All things given she’s more likely than Jo.
Why it’s not likely: Honestly I think if Danny is covering for someone, Lacey is the most likely choice. The only difficulty is I don’t see Lacey as Regina’s killer too as that would severally restrict where they could take the character. Of course while there may be a connection between Regina’s death and the aunt’s, it doesn’t follow that the killer has to be the same.
Why it’s likely: Danny’s mother is definitely an attractive option. Danny would very naturally want to protect his mother. Especially if his mother told him if he took the fall he’d only be sent away for a few years, while she would get a much longer sentence. Also we’ve already been told she was the head of the social scene and that it mattered a great deal to her, maybe the aunt threatened that somehow.
Why it’s not likely: Karen and Danny’s relationship seems to be on pretty solid footing so far. While he has some issues, especially with the fact she made him come back to town, he seemed to accept her explanation and let go of his resentment. Also he thanked her, when she expressed her faith in his innocence with regards to Regina. Would he really thank you if the only reason she believed in him was because she knew he wasn’t a killer because she is and they both know it?
Why it’s likely: The aunt was his sister. Already there’s a strong connection there. The fact that he went missing five months before Danny was released, could be explained away by the fact that he couldn’t bear to see the son who went to prison for him, or Danny threatened him into leaving.
Why it’s not likely: It’s possible Danny knows he faked his death, but it’s harder to understand why he wouldn’t share the truth with Jo when she asks him, nor why he’s protecting her by not telling her.
Why it’s likely: It could almost make sense that Danny might take the fall to protect Jo from learning her father is a killer. It would also explain his continual refusal in the present to tell Jo the truth. Motive could easily be explained by Kyle having an affair with the aunt. And Kyle would certainly be in a position to know taking Regina’s necklace would implicate Danny, and he might very well want to get rid of Danny under the circumstances. Also he’s certainly not too happy at the sight of Danny.
Why it’s not likely: Despite Kyle being a police chief and Jo’s father, I find it a little harder to believe Danny would take the fall for him, or that Kyle could believe he could convince an eleven year old friend of his daughter to confess to a murder he didn’t commit. While I think Kyle is one of the more interesting options, I also don’t think he’s a very likely one.
Personally, until we hear a bit more about what he has to say about the matter I’m still pretty convinced Danny is guilty. But of all the people he might have taken the fall for, Lacey seems the most likely. The strongest argument for his innocence was his line to Jo ‘I may have killed someone before, but I never lied to you’. This line would make complete sense if he had really killed his aunt. However the ‘may’ still sends up some red flags.