Investigating a killing by Saudis, an authoritarian regime that quite obviously murdered the guy even without an investigation, is analogous to a democratic ally that investigated a killing in a war zone with the cooperation of the Americans?
Is that a joke?
And the US investigation that took place happened with the Saudis? The US can investigate this one the same way without Israeli cooperation. Have at it.
You keep ignoring the fact that the US not investigating these deaths until this one particular case, and even then, only after months of silence, proves it is a political stunt. The fact that you are for all deaths being investigated has no bearing on that. This is a political stunt whether you are in favor of such investigations or not.