Based on the available evidence, the killing of Ambassador Andrei Karlov is more similar to the murder of Abraham Lincoln than to any of the other theories, some of them hare-brained, that have been proposed: such as the usual unsubstantiated spouting about the CIA, the Mossad or that the Russians did it to themselves.
The Russian and Turkish official interpretations, that it was intended to disrupt improving Russian and Turkish relations and that it was timed just a day before a Russian-Turkish-Iranian summit on Syria in Moscow, make huge assumptions on the part of the killer, Mevlut Mert Altintas. It is assumed he even knew about the summit and was thinking strategically about diplomatic relations between his country and Moscow.
But why assume when we have his own blood-curdling words? After his dastardly deed he shouted “Remember Aleppo! Remember Syria!” and ““We die in Aleppo, you die here,”
plus explicitly calling his act “revenge for Syria and Aleppo.”
Again based on what we know, this was clearly a revenge killing for losing a war, or at least a major and perhaps the decisive battle of a war.
This crazed cop may well have been further incensed by all the unproven allegations of genocide, and massacres and burning children in east Aleppo that were irresponsibly spewed by Western and Turkish leaders and media.
Mostly though, like John Wilkes Booth, he was out of his mind with anger that his side had lost and he took his revenge on a leader of the country that beat him. In the same vein as Altintas, Booth cried, “Sic semper tyrannis! (Ever thus to tyrants!) The South is avenged.” Both assassinations happened at cultural events in full view of the public.
Booth had co-conspirators who were hanged, and Altintas may have had his, but that remains to be seen.