A Bosnian Croat wartime commander died on Wednesday shortly after he drank poison, seconds after U.N. appeals judges upheld his 20-year sentence for war crimes against Bosnian Muslims.

Slobodan Praljak, 72, a former wartime leader, tilted back his head and took a swing from a flask or glass as the judge read out the verdict. The man’s defense lawyer then told the court that the accused had “taken poison.” The presiding judge stopped the proceedings and ordered a doctor to be called, Reuters reports.

“I just drank poison,” he said. “I am not a war criminal. I oppose this conviction.”

Praljak sat back down and slumped in his chair, a lawyer who was in the courtroom at the time said. The presiding judge suspended the hearing and called for a doctor. An ambulance was at the building and paramedics went to the courtroom.

Praljak was convicted of involvement in a campaign to drive Muslims out of Bosnia and create an ethnically pure Croat state during the Bosnian war in the 1990s sparked by the breakup of Yugoslavia. The conflict mainly saw Bosnian Muslims fighting Bosnian Serbs, but there was also deadly clashes involving Bosnian Muslims and Croats after an alliance fell apart. A total of 100,000 people died and 2.2 million were displaced in the three-year war.

Quoted by Reuters, Croatian General Marinko Kresic told Croatian state TV he had spoken to the wife of another defendant, General Miroslav Praljak, who was in The Hague. “She confirmed that he drank the poison and that he is in a very grave health condition,” he said.

Praljak died shortly after.

A UN judge who later called the site a "crime scene" said that Dutch police are investigating the incident.

As Reuters adds, the court said it would resume reading the verdict, which is also handling cases against five other defendants, including Milivoje Petkovic.

Prior to drinking the substance, Praljak had heard that his 20-year sentence for alleged war crimes in the Bosnian city of Mostar was being upheld. Praljak, who was one of six former Bosnian Croats having their appeal heard at the UN tribunal, is reported to have told the judge that he is not “a war criminal.”

The dramatic events came in the final minutes of the court’s last verdict before closing down. The International Criminal Tribunal for the former Yugoslavia (ICTY), established by the United Nations in 1993, shuts its doors next month when its mandate expires. The court’s lead suspect, former Yugoslav President Slobodan Milosevic, died of a heart attack in March 2006 months before a ruling in his genocide case.

Two defendants awaiting trial committed suicide by hanging themselves in their U.N. cells, according to court documents. Slavko Dogmanovic died in 1998 and Milan Babi? was found dead in his locked cell in 2006. Last week, the same tribunal handed former Bosnian Serb general Ratko Mladic a life sentence for his role in the genocide of the Balkan Wars in the 1990s. Mladic was found guilty on 10 out of 11 charges, including the massacre of Bosnian Muslim men and boys in Srebrenica in 1995. He had pleaded not guilty on all counts.

Questions have been raised over the fairness of the international prosecution of crimes committed during the Balkan Wars. Of the 161 individuals indicted by the ICTY, the body created specifically to prosecute wartime crimes, 94 are ethnic Serbs, compared to 29 Croats, nine Albanians and nine Bosniaks. Two years ago, Russia used its UN veto right to block a resolution on the 20th anniversary of the Srebrenica tragedy, saying that the draft document depicted the Serbian people as the sole guilty party in the complex armed conflict in Yugoslavia.