Let’s assume she killed him exactly this way, then climbed up and ran frantically into the ranger station, saying he had slipped and fallen over the edge.
How in the world would it ever have been prove “beyond a reasonable doubt” that she had indeed murdered him?
It ppears to have been her clumsy lies that tripped her up. If she’d (mostly) just told the truth she’d probably have gottenaway with it.
Fortunately she wasn’t capable of maintaining a facade.
IMO she should be hanged for premeditated murder.