I believe that Brad Cooper is guilty of the premeditated murder of Nancy Cooper. I do not understand how this murder could have been committed by Brad and not have been premeditated.
It's an interesting case. If the murder was not premeditated, and the phone calls were not spoofed, then Nancy did phone Brad in the morning ... she was alive shortly before 7, and then Brad's alibi of looking after the children is as solid as JP's alibi of looking after the children.