PARIS—The moment was dramatic enough: In a courtroom in The Hague on Wednesday, a military commander from the former Yugoslavia pulled out a small bottle and drank from it, declaring that he had ingested poison to protest his conviction for war crimes. The judges quickly ordered that courtroom curtains block the view of spectators in the public gallery. Live television coverage went dark.

But what happened next, beyond public view, was just as shocking, according to lawyers and court officials. The war criminal, Slobodan Praljak, 72, slumped in his chair and began to gasp for breath. He was later taken to a Dutch hospital and pronounced dead.

On Friday, Dutch prosecutors announced that Praljak had died of heart failure after ingesting potassium cyanide — a highly toxic compound — and the International Criminal Tribunal for the Former Yugoslavia announced that it would conduct its own “independent, expert review” of Praljak’s suicide. But the key questions — how he managed to smuggle the poison into court — remained unanswered.

Read more:

War criminal Slobodan Praljak appears to kill himself with poison seconds after losing appeal

Autopsy shows dead war criminal Slobodan Praljak had cyanide in system

Defense lawyers at the tribunal say the security arrangements in force for defendants like Praljak and the five other men whose sentences were affirmed Wednesday were rigorous, with body searches when they left their detention centre — inside a high-security Dutch prison — and again when they arrived at the tribunal building. But, the officials acknowledged, one form of search — of body cavities — is not part of the routine.

Even so, that left the question of how Praljak could have laid hands on the toxin since visitors were supposedly searched, too. And in the months before his final appearance in court, he had seemed to eschew contact with his family and his lawyers.

Nika Pinter, his lead counsel, said in a telephone interview from Zagreb, the Croatian capital, that Praljak had told his family not to be present at the judgment.

“For 13 years, his wife came to visit him in prison every month, the last time I think at the end of October. His stepson and stepdaughter would also visit,” Pinter said. However, she added, “He forbade his wife to listen to the judgment. And he told her: Don’t come to The Hague.”

Pinter recalled: “Last weekend I called him and asked him if he would like me to visit him before the judgment. He said: ‘No, don’t come.’ I called again on Tuesday and told him I would come to court early to meet him. He told me: ‘No, don’t come. I’ll see you in the courtroom.’ ” She said she believed he wanted to spare her from what followed.

“From the start, 13 years ago, he told me he could not bear being called a war criminal,” Pinter said. “He couldn’t live with the stigma.”

But she added: “He never gave a hint that he was planning to end his life.”

Praljak had been a theatre and film director and a writer. He joined the Croatian army and was named a general when it was formed after the country broke away from Yugoslavia in 1991.

Named commander of the Croatian forces fighting in Bosnia, he was a key figure during the conflict, including the long siege and shelling of the ethnically mixed city of Mostar. At the time, he was the main liaison between political and military leaders in Croatia and the Croatian force fighting in Bosnia.

He surrendered to the tribunal in 2004 and was convicted of war crimes and crimes against humanity in 2013. He was sentenced to 20 years in prison, but appealed. (He would have been due for release in 2019, after serving two-thirds of his sentence, including time served.)

The tribunal had just affirmed his verdict and sentence Wednesday when Praljak kept standing.

He reached forward to pick up the vial.

“Slobodan Praljak is not a war criminal,” he declared portentously, in Croatian. “I reject your judgment with contempt.”

Loading... Loading... Loading... Loading... Loading... Loading...

He then opened his fist, took out the vial, tilted back his head and drank.

“I have taken poison,” Praljak said. One of his lawyers, Natacha Fauveau Ivanovic, called out to ensure that the presiding judge, Carmel Agius, understood: “Mr. President, our client says he took poison.”

The judges were stunned, but appeared not to have fully grasped what had happened. Agius directed the next defendant to rise and began reading.

“People did not realize exactly what was going on,” said Michael Karnavas, a veteran defence lawyer representing Jadranko Prlic, one of Praljak’s co-defendants. “This man was always full of bravado. Prajlak sat down and almost immediately he was gasping for air, struggling to breathe. It was loud. He made sounds like he was choking. I saw him slumped in his chair. Someone shouted for help. The guards came over and got him onto the floor.”

Karnavas added: “After a few minutes two medics arrived from the medical office in the tribunal. One of the medics calls out: The heart has stopped. They start doing CPR, they are pumping his chest to get his heart going, taking turns with some of the security guards.”

After 20 minutes, an emergency team arrived from a local hospital and took over. They kept him in the building for about an hour because they wanted to stabilize him. It was not clear what made the medical team finally decide to take him to the hospital. Croatia’s justice minister has called into question the speed of the responses by security and medical staff.

The tribunal said on Friday that its inquiry would be led by Hassan B. Jallow, the chief justice of Gambia and a former prosecutor at the International Criminal Tribunal for Rwanda.

A report on the findings is expected by Dec. 31. It was unclear to what extent those findings would be open to scrutiny.

“The outcome of the review will be made public, subject to due process and confidentiality considerations,” the tribunal said.

To smuggle the vial into the courtroom, Praljak had to circumvent what were supposed to be tight security arrangements. The defendants are escorted by guards and enter the building through an underground parking lot. They are strip-searched when they leave the detention unit and then again at the court. They are unable to have contact with members of the public.

Visitors also face tough security checks, said Fauveau Ivanovic, the defence lawyer, first to enter the high-security Dutch prison, and then again at the U.N. detention unit set within the compound.

“Everything — our shoes, our clothes, our bags — everything goes through the X-ray machine,” she said. “We walk through a scanner, like at an airport. We can’t bring in liquids.”

Karnavas recalled the last time he saw Praljak. “I last saw him outside the courtroom that morning as he was coming out of the toilet,” he said. “I thought nothing of it at the time. But I’m thinking about that now.”