I saw Precious (the movie) for the first time the other day. For those who have watched it, remember the final scene where Mary is telling Ms. Weiss why she loved and hated Precious? That, in a nutshell, is how I feel Billie felt about Hailey. I think she knew Shawn either wanted Hailey or had been doing something to her. I think Billie snapped on December 26 when she walked in on him trying and/or touching Hailey. I think she killed her in a fit of rage and made Shawn help her clean it up. Now, she "has her man" all to herself and by the proverbial cajones too because if he ever were to betray her, she takes him down. They are both guilty: Shawn for being a pedophile, Billie for being a narcissistic jealous mother and both are guilty for Hailey's murder.