@Olivier5,
Olivier5 wrote:They have nothing to win out of killing him,
That is incorrect. Killing him would achieve the justice that we are denied by his exile.
BTW, you make it sound like this would be something that individual agents (or perhaps the CIA as a whole) would just decide to do on their own.
America's intelligence agencies act on the orders of the US president, and I was envisioning the same in this case as well.
As for people knowing that it was the US, perhaps the US government could follow Israel's lead and engage in over-conspicuous gloating after a successful assassination, just to make sure that everyone has no doubts.