That said - if it was done with a gizmo or a bunch of guys the remarkable thing is that they got it or them into and out of the country. That the says something either about the competence of perpetrator or the incompetence of the Iranians.
We've been assassinating for thousands of years. Theres no precedence. This event will be forgotten in a week and probably will never be in a history book due to how mundane the killing was. The term assassin is old as hell for a reason.
> If China or Russia
If? It's been happening forever
https://en.m.wikipedia.org/wiki/List_of_Israeli_assassinatio...
https://en.m.wikipedia.org/wiki/List_of_Soviet_and_Russian_a...
https://en.m.wikipedia.org/wiki/Rise_and_Kill_First
Just in very recent history, and we only know about them because they were high profile:
https://en.m.wikipedia.org/wiki/Poisoning_of_Sergei_and_Yuli...
https://en.m.wikipedia.org/wiki/Assassination_of_Qasem_Solei...
https://en.m.wikipedia.org/wiki/Assassination_of_Jamal_Khash...