“He was entrenched” in the operation and “participated with resolve,” they wrote.

His “robust participation in all aspects of the plan demonstrates that he not only knew of the intent to destroy” the group, but that “he also shared it,” the panel said.

Image Lt. Col. Vujadin Popovic, 53, and Col. Ljubisa Beara, 70, from left, back row, were convicted in The Hague on Thursday of genocide for the massacre of Muslims in Srebrenica in 1995. Credit... Pool photo by Lex Van Lieshout

Colonel Beara, chief of security of the army main staff, ranked above Colonel Popovic. As the most senior security officer, “He had the clearest overall picture of the massive scale and scope of the killing operation,” the judges said. He organized logistics and became the massacre’s “driving force.” He located detention and execution sites and recruited people to help with the killing and the digging of mass graves, court documents said.

A third Bosnian Serb Army officer, Drago Nikolic, 52, was found guilty of aiding and abetting genocide and sentenced to 35 years.

The four other defendants were convicted of crimes against humanity and other wartime atrocities. Among them were two generals: Radivoje Miletic, 62, who was sentenced to 19 years, and Milan Gvero, 72, who received a five-year prison term. Vinko Pandurevic, 50, a brigade commander, got 13 years, and Ljubomir Borovcanin, 50, a police commander, was sentenced to 17 years.

Genocide has proved difficult to prosecute. The concept, as defined in the 1948 United Nations resolution establishing the crime, goes beyond mass murder, requiring proof of “intent to destroy, in whole or in part, a national, ethnical, racial or religious group, as such.”

The three-judge panel at The Hague ruled that the definition had been met.

“The scale and nature of the murder operation, with the staggering number of killings, the systematic and organized manner in which it was carried out, the targeting and relentless pursuit of the victims, and the plain intention  apparent from the evidence  to eliminate every Bosnian Muslim male who was captured or surrendered proves beyond reasonable doubt that this was genocide,” the judges wrote.

The genocide finding is likely to have an impact well beyond this trial. In Bosnia, Zumra Sehemerovic, who represents an association of massacre survivors, said the recognition of the crime was essential to the victims.