My theory is he strangled Karen the previous evening or pushed her down the stairs, SR was present, BR's phone records show he was awake during the night. One of them used her email / whatsapp in the morning (BR would all be familiar with the correspondence) as an alibi she was still alive and to cover SR's knowledge, SR went to work, BR placed Karen's body in the Mercedes, drove to Macedon and when he returned he bleached the ensuite.
Reasons why I believe SR had knowledge -
1. Her body language at the initial press conference - she didn't present as a worried daughter who's beloved mother was missing for several days. She appeared TERRIFIED, didn't make a heartfelt plea to the public as would be expected, crying but no tears, and once BR asked if he killed his wife, her body language became overly self protecting (stooped). She also justified why she was asking her Mum to come home stating because she is an only child. Irrelevant and suspicious given a genuine plea would focus on emotional aspects.
2. SR was the ONLY hostile witness during the Committal Hearing, she lacked emotion even though it was reported she was emotional (she was for approx 10 seconds of approx 40 mins in the witness box). She did not distinctly offer a kind word about her mother (which I expected) nor try to defend her when discussing her parent's relationship. Instead she left that for the following witness who worked with Karen who talked about Karen very fondly.
3. During the Committal Hearing SR changed her previous sworn statement regarding whether there were any of her mother's shoes missing. She stated initially no shoes were missing, but had since realised there was a pair missing.
All IMHO.
