Rock Bottom: The Death of Rinette Bergna

Peter Bergna picked up his wife Rinette from the airport and drove up Slide Mountain near their home to talk about their marital problems. According to Peter, the brakes on his truck malfunctioned, causing the truck to crash through a guardrail and nosedive off of an 800-foot cliff. Peter was lucky. He had somehow been expelled from the driver’s side window and landed without serious injury on the upper slope of the mountain. Rinette was not so lucky. Her broken body was found inside the crushed truck hundreds of feet below.
Peter was the only one left alive who knew what had happened between the airport and the crash. Police attention turned to him first because of his odd behavior at the scene and then after a forensic analysis of the crash was done. Reports of infidelity and verbal abuse strengthened suspicions.
Our quiet end case today is Rock Bottom: The Death of Rinette Bergna. Did Peter plot the murder of his wife, and if he did, would prosecutors be able to convict him of the crime?