I disagree. There are several of these cases that have happened here in the US.
https://www.nbcnews.com/news/us-news/colorado-man-sentenced-life-pushing-wife-death-cliff-n476726
https://www.nbcphiladelphia.com/news/local/new-jersey-wife-cliff-push/25863/
https://people.com/crime/oregon-man-pleads-guilty-girlfriend-cliff-murder/
Of course, remember the Montana woman who pushed her husband of only eight days off a cliff in Glacier National Park?
Why didn’t he throw her off the cliff? Obviously an accidental fall would have been his alibi. I maintain that it wasn’t planned.