Dutch police say they have failed to discover how a defendant on trial at the Yugoslavia war crimes tribunal in The Hague was able to take poison and kill himself after hearing the verdict.

Slobodan Praljak, 72, died in hospital just under a year ago, after swallowing liquid from a small bottle. He took the poison, in full view of the cameras, after hearing his 20-year jail term for war crimes had been upheld.

The public prosecution department said on Friday ‘the investigation has not shown in what way and at what point in time Praljak had obtained the potassium cyanide he used.’

‘No criminal offences were established,’ the department said.

The department’s efforts focused on trying to establish how the bottle with poison had made its way to the court room. ‘Camera footage was studied, several witnesses were interviewed, the rooms where Praljak had stayed were searched and documents and data carriers were examined,’ the department said.

‘However, no information was discovered clarifying how and when he had obtained the poison.’

Holding cells

Prior to the court ruling, Praljak was held briefly in two rooms without camera surveillance: the toilet and the holding cells. Nothing relevant was found in those rooms afterwards, the department said.

In 2013, Praljak, the ex-commander of Bosnian Croat forces, was sentenced for crimes in the city of Mostar during the Bosnian war from 1992-95.

The department says that witness statements show Praljak had been considering suicide for some time. He had already had his items packed for shipment to Croatia and said goodbye to people on several occasions.

After Praljak’s death, officials found a farewell letter to his family in which he said that he had already decided to put an end to his life a long time ago, should he be found guilty.

This could mean Praljak had the poison in his possession for a (very) long time. Potassium cyanide can be stored in its dry form and suicide only requires a very small quantity, the department pointed out.