She hasn’t told them that Robert told her that night that he suspected Amanda was having an affair. She’s afraid if the police know, they will think he has a motive. And she hadn’t told Robert, when she was lying in bed with him, that she knew who Amanda might be having an affair with. She won’t tell the detectives what she saw. Not unless it becomes absolutely necessary. Because she knows who Amanda’s lover is. And there’s no way he killed her either.
