Aleksey Kutsurubenko, head of the investigative department of the “DPR” Prosecutor General’s Office, confirmed that a large number of civilians were initially hiding in the Mariupol Drama Theater, which killed about 600 people as a result of the strike. He told RIA Novosti that all these residents allegedly left the drama theater before the Russian strike. However, in May it became known that the Russian military could have removed some of the human remains from the airstrike to hide the number of victims.
Also, the Prosecutor General's Office claims that the explosion in the drama theater "occurred from the inside through the fault of the Armed Forces of Ukraine": a non-enveloped device allegedly exploded inside the building, as a result of which 14 people died. Investigators "did not find submunitions or other signs of an airstrike."
“In the building of the drama theater, military personnel of the Armed Forces of Ukraine equipped firing points. The building was used not only by civilians as a bomb shelter, but also by the military itself for combat operations. As some eyewitnesses explain to us, just when the Ukrainian Armed Forces began to arrive in the building, civilians began to leave it.”
According to Kutsurubenko, at first a large number of civilians hid in the room, but by the day of the tragedy, there were “virtually none left” in the drama theater. At the same time, he admitted that there was a humanitarian aid point in the theater: food was distributed to people there.
The attack on the Donetsk Regional Academic Drama Theater in Mariupol was inflicted on March 16 by Russian aircraft. In June, the international human rights organization Amnesty International, during the investigation, concluded that the Russian strike on the drama theater in Mariupol was a war crime. Amnesty International Secretary-General Agnès Callamard said the International Criminal Court should investigate the crime. Among other things, the human rights organization commissioned the physicist to build a mathematical model of the explosion in order to determine the mass of explosive that would be required to cause such destruction. He concluded that the Russian fighter dropped two 400–800 kg bombs that exploded simultaneously. Most likely, the strikes were carried out by Su-25, Su-30 or Su-34 fighters, which were based at nearby Russian airfields and often operated over southern Ukraine.
Associated Press journalists who interviewed eyewitnesses concluded that about 600 people died as a result of the strike. In order to estimate the number of victims, the news agency also used two plans of the theater premises, photographs and videos that were taken both before and after the airstrike, the conclusions of experts. Before that, the authorities of Mariupol came to the conclusion that 300 people were killed during the bombing of the theater: this figure was given by two surviving witnesses. Due to the inability to find the remains of those who died after a powerful explosion, a police officer and a Red Cross employee concluded that there were fewer than 500 victims. AP suggests that some of the human remains could have been removed from the site of the airstrike by the Russian military, who occupied the territory of Mariupol.