Prosecutors will be allowed to present more gruesome evidence against a former Bosnian Serb military commander who has been on trial for genocide since 2012.

A United Nations-backed International Criminal Tribunal for the former Yugoslavia announced Thursday that the court will hear details about a mass grave investigators believe has ties to Ratko Mladic. Investigators discovered the site in 2013 in the village of Tomasica, a haunting reminder of the bloodshed wrought by the conflict that followed the breakup of the former Yugoslavia two decades ago.

The former commanding general of the Bosnian-Serb forces is accused of leading a campaign of "ethnic cleansing," widespread killing, torture, forced labor and physical, sexual and psychological violence during the Bosnian war.

More than 400 remains recovered at the Tomasica site are suspected to be of Bosniak and Croat ethnicity from Prijedor and its surroundings -- people killed in summer 1992, according to the Prosecutor's Office of Bosnia and Herzegovina and the international tribunal.

In 1992, Mladic led the siege against Sarajevo, which killed thousands of people, including civilians, and lasted more than two years. He also spearheaded the attack on the Muslim enclave of Srebrenica, where an estimated 7,000 men and boys were killed. In 1995, the United Nations International Criminal Tribunal for the former Yugoslavia indicted the ex-commander, along with 51 others, on charges of war crimes and atrocities.

By the time an international arrest warrant was issued for him and he finally turned himself in, Mladic had gone into hiding and wasn't apprehended until 2011.

In July 2011, a tribunal judge entered not guilty pleas for Mladic after he refused to cooperate and was forcibly removed from the courtroom at the judge's order.

His trial began in May 2012. In court, he dragged his hand across his neck as if cutting a throat while staring at victims of the war.

On Thursday, the tribunal said Mladic's defense team will have "ample opportunity" to present evidence in response to the latest allegations.

He's facing life in prison.

(CNN)