Cindy picked up the phone and not Jane (as we didn't see who)
Cindy went into a panic telling Jane "what do I do?? he knows I did it.."
Jane tells her to leave and will sort it and talk to Ian
further twist maybe Jane THOUGHT Bobby did it, covered it up and then found out it was actually Cindy.....
Ian doesn't tell the police because he loves Jane and knows she would go to prison too.. Peter leaves because he doesn't want to live with the person who killed his sister..