I am not sure if Lily killed her mom. When I watched the movie version of the book, the film insinuated that she did. But when I read the book, the way T. Ray acted made me suspicious. On page 18, Lily tells T. Ray that she remembers the moment when her mom died and T. Ray is really nervous. He yelled at her, “You were four years old! You don’t know what you remember!” and then he gets really scared. “He stood there for a minute, his hands balled up before he turned around and came back. ‘What else?’ he said. ‘You tell me right now what you know!” He said this as if he was afraid that she could tie him back to the murder. The books said he looked at her suspiciously, and when she said she couldn’t remember after the gun went off, he puts his hands on her shoulders, looking at her intently, and tells her that she did it. They way he does this almost looks like he is teaching her what happened, rehearsing lines. At the end when he almost kills Lily with a knife thinking that she was her mom, she said that it seemed very possible that he could have killed her. And when he leaves, she said that he looked like he was telling the truth but you never knew with T. Ray. I think that he accidently killed her and because she was coming back for Lily and not him, he blames Lily. And he doesn’t want to go to jail for her murder.
I felt like that too after finishing the book. I did like that the author left it unsolved; I feel like that's more realistic. And it was obviously a successful move on her part since we're still talking about it after finishing the book. :-) I thought the story of Lily picking up the gun and it accidentally going off was a little fishy in the beginning, but T. Ray's behavior at the end solidified my thoughts that he did it, not Lily. Lily's so afraid of her father, I don't think that at four years old she would have been brave enough to go out and grab the gun to hand to her mother.
I think she did shoot her mom. It explains T. Ray's overprotective attitude. I think he was always afraid of people telling Lily what had happened and scaring her even further than what she had been scared with losing a mother. I think he projects what happened that night to the moment when T. Ray tries to go after Lily with the knife. Overall I just think that T. Ray was like May and they had deep suffering that turned them into something that they couldn't get out of.