Originally Posted by curvybabes:
“Surely Bobby must realise he killed Lucy.”
Of course he should. He bangs his sister over the head and she doesn't wake up. He panics and calls his mother, so he knew something was wrong. Then he finds out the next day she's dead.
I suppose the only thing in his mind that he didn't do it is that she was found on the common. He obviously hasn't twigged she was moved, so believes she went there of her own accord.
But seriously, even if Ian and Jane manage to cover it successfully, give it a year or two and he'll piece it together himself anyway.