What for? The Bloody Sunday massacre in 1905? The Tsar didn't order that, and he wasn't even in St. Petersburg at the time.
The tsar's call for war puts him at blame for Russian casualties pre-1917.
An estimated 25,000-140,000 Germans died during the forced deportation from Volhynia.
The death count is unmeasured for that of POWs held and tortured by the tsar's forces during the war.
The invasion/massacre of Northern & Eastern Turkey was an orchestrated mass murder of Turks and Kurds.
There were countless lives lost as a result of the Czar-encouraged Pogroms.
Nicholas II was an autocratic tyrant and mass murderer if there ever was one.
That logic would make every wartime leader in history a mass murderer. "Mass murder" as a charge works best as intentionally killing civilians, especially in peacetime.
An example of a mass murderer during World War I would be Enver Pasha intentionally trying to wipe out every man, woman, and child of Armenian heritage on the premise that the entire ethnic group was a Russian fifth column.
Edit: Fixed typo.
