Wow. Everything points to premeditation. Now, why wasn't he telling everyone in the family that he would be fishing? I wonder if he told the guy behind the counter when he got the fishing license "This is just in case it's too cold to golf on those days."
Until this revelation about the fishing license being purchased for the exact dates of 23 and 24 Dec, I was sure this was an accidental death, a violent argument leading to her demise.
What a dastardly deed this was.