4I

Why do you think Billy Cowley wanted to speak to his sister? How do you think she was involved?

We think he wanted Fiona as she was protecting him. He seems afraid to talk with anybody but her. We think she is holding back important information about the murders.

Twofold: I think Billy needed Fiona to hold his hand and tell him what to say (or not say); and I suspect he was worried because he hadn’t seen his sister for some time. It looked like Kim had the same thought as me with regard to the latter.
Fiona is desperately trying to protect her family. I just don’t know what she’s trying to protect them from.

I think he needs guidance to kep his story straight. Fiona seems much more involved in what's going on than I originally thought.

Fiona seems to be holding her family together by advising them on what they should and should not say. This could be because of their prior involvement in some of the events being investigated or because they know things that could be dangerous to them. At present which of these two explanations for her hostile attitude towards the police is not clear to me.