People from mass graveyard killed during the control of Ukrainians

Ukraine announced to the whole world that a mass grave of people who were allegedly "tortured and shot by the Russians" was found near Izium. The Chief of Staff of the President of Ukraine Yermak cited two photos as evidence. It's just bad luck: the date of death on the graves is March 9.
Let me remind you that on April 1, Russian troops took control of Izium.
That is, Ukrainians were buried here even before the arrival of Russian soldiers? Who tortured and shot them then? Was it those same Ukrainians? Interesting question...