David Blake Knox writes: Thirty-five years have now passed since civil war erupted in the Balkans. In 1990, the Yugoslav federation began to tear itself apart, with insurrections breaking out in most of its six constituent republics. Wars in the Balkans have book-ended and characterised much of the twentieth century in Europe. This one proved to be the most serious conflict on European soil since World War Two.
One story from the Yugoslav civil war connects a small valley in rural England with a mass grave in Croatia. At its heart is a dreadful crime – involving murder, betrayal and deceit – and a struggle between those who sought to reveal the truth, and those who wanted to deny and suppress it. That conflict was resolved by a most unlikely witness: a walnut tree.
One spring morning in 1998, Paul Tabbush was at work at the Bedgebury Pinetum in Kent – one of the world’s largest collections of tree specimens – when he received an unexpected phone call. Prof Tabbush was head of silviculture and seed research with the British Forestry Commission. To his astonishment, the phone call he received that morning came from an investigator with the War Crimes Tribunal in The Hague.
The investigator was a Czech detective called Vladimir Dzuro. He was a big man with a forceful manner, but he had a shrewd and agile mind and had proved himself to be a dedicated detective. He had worked as a senior police officer during the old communist regime in what was then Czechoslovakia. After the fall of the Iron Curtain in 1989, he became the chief security officer for the UN in Sarajevo. Soon after that, he joined the War Crimes Tribunal, based in The Hague. His first big job was to investigate a massacre that had taken place near the Croatian town of Vukovar in 1991.
Vukovar is a historic part of Croatia, but, following World War Two, it became part of a new state: the Socialist Federal Republic of Yugoslavia. In the aftermath of the world war, all of the town’s ethnic Germans were expelled and replaced by settlers from Serbia. When war erupted in Croatia, around 30 per cent of Vukovar’s inhabitants were ethnic Serbs and many of them were sympathetic to the aggressive Serbian nationalism of Slobodan Milošević.
Throughout 1991, members of the Croatian National Guard defended Vukovar against the assaults of more than 30,000 Serbian soldiers. Those forces consisted of what had once been the Yugoslav regular army, augmented by local Serb militias and supported by artillery and heavy armour. In November of 1991 – after months of intense fighting – the town fell to the Serbs. The last redoubt for the Croat fighters was the town’s hospital – which is where they were taken prisoner by Serb troops. When the Croats surrendered, they believed that their safe passage out of Vukovar had been agreed but instead they were disarmed and around 300 of them were bused to a nearby pig farm at Ovčara. They were, at first, held in a large shed. Then they were taken in groups of ten to twenty prisoners to a prepared site at a nearby ravine, where they were shot dead. Their bodies were thrown into the ravine and, when the massacre was complete, the grave site was filled with soil and rocks.
Almost all of the Croats were killed –though a few were allowed to live. Some of these had claimed they were ethnic Serbs who had been forced to serve in Croatia’s National Guard. One of the survivors was the town’s sanitary inspector, Emil Cakalić. He claimed to have recognised the man who was directing the massacre: according to Cakalić, it was Vukovar’s mayor, Slavko Dokmanović. If what Cakalić said were true, then the mayor of Vukovar had taken part in the mass murder of hundreds of his own neighbours.
In the months that followed, more than 20,000 ethnic Croats were expelled from Vukovar and Dokmanović became the minister for agriculture in the new breakaway Republic of Serbian Krajina. By 1996, he had moved from Vukovar to become a senior politician in Serbia proper – where he was regarded as one of Milošević’s most trusted and loyal lieutenants. By 1996, however, Vukovar was back in Croat hands – as part of the Erdut peace agreement – and war crimes investigators with the International Criminal Court began to dig up the dead.
The man who had to piece all the evidence together was Vladimir Dzuro. Working with a small detective team, he was able to locate the mass grave of the Ovčara massacre and started to exhume the bodies. By the end of 1996, 200 sets of human remains had been recovered from the ravine, and another sixty bodies were found close by at other grave sites. By 1997, Dzuro was satisfied that he had enough to convict Dokmanović of mass murder.
But, by then, the former mayor of Vukovar was safe in Serbia, and it seemed that he could evade any attempt to arrest him – and so a trap was set. Dokmanović was invited to a wedding close to the Serb border. He decided to attend – and the trap was sprung. Dokmanović was taken prisoner by a unit of Poland’s special forces and flown directly to The Hague under a sealed indictment to be tried by the International Criminal Court.
In the coming months, his defence council filed a number of motions for his immediate release. All of these were rejected by the court and a trial date was set for January 1998. When the court met, it heard harrowing testimony from the survivors of the Ovčara massacre and this was corroborated by the forensic evidence of the bodies that Dzuro had recovered. However by this time Dokmanović and his associates had seen how the court worked and had clearly learned some lessons.
When Dokmanović filed his defence, Dzuro realized that a conviction was far from certain. Although a number of witnesses could place him at the scene of the Ovčara massacre, there was no forensic evidence linking him to it. There were also eight alibi witnesses – all of whom gave sworn testimony that they were with Dokmanović and far from Ovčara on the day that the massacre took place. What is more, his defence claimed to possess material evidence which would confirm his alibi. Someone had shot a video – with a burnt-in time-code – and the tape seemed to prove that Dokmanović was not close to Ovčara at the time of the massacre. Dzuro suspected that the tape was a fake. To prove that, he sent it for analysis to the world’s most advanced forensic laboratory – run by the FBI in Quantico, Virginia. But even the FBI’s technology couldn’t establish whether or not the tape had been foxed. Dzuro was forced to revert to simpler forms of detection. He went back to Vukovar in person and tried to match what the video showed with the actual lie of the land.
Dzuro filmed the same journey that Dokmanović claimed to have taken out of Vukovar on the day of the massacre. Then he and his team compared what he had shot – frame-by-frame – with the video that appeared to provide Dokmanović with an air-tight alibi. Dzuro noticed a number of discrepancies between the photos he had shot and the footage in Dokmanović’s video.
In particular, Dzuro focused on two images that appeared on the alibi tape. The first was recorded in the car that carried Dokmanović away from Vukovar. The other was apparently recorded later – when Dokmanović’s car appeared to be close to the village of Negslavci several miles away. The time-code burned on that footage seemed to prove that Dokmanović could not have been at the site of the massacre when it took place. However, Dzuro had identified a number of specific landmarks on Dokmanović’s tape and he thought that he recognised one of them on the southern outskirts of Vukovar. It was a specimen of Juglans regia – a walnut tree. In 1991, this tree was young and small. But Dzuro had noticed something odd about the walnut tree as it appeared in Dokmanović’s video. It seemed to have been filmed, first, from one side of the road – and then, at a later stage of Dokmanović’s journey, from the other side.
Dzuro realised that, if he could prove that the tree were the same one in both shots, it could only mean one thing: Dokmanović’s video did not only show him leaving Vukovar, as his defence had claimed. Instead, it revealed that his car had made a U-turn and had headed back towards the town. In other words, if the tree were the same one, then the tape had been doctored to provide Dokmanović with an alibi.
It was at this point that Dzuro contacted Prof Tabbush. He had no idea whether or not Tabbush could prove that what had seemed like two different walnut trees in the video were actually the same one. But he soon discovered that Tabbush knew a simple but basic truth that applies to all trees. Their branches grow from their tips – which means, as they grow, the angle of each branch to the stem does not change. If the angles of the branches of the walnut tree that Dzuro had found matched those in the video, then it was the same tree.
Later, in court in The Hague, Dokomanvić’s defence drew attention to the failure of the FBI to find that the video tape had been doctored. Dokomanvić’s counsel also tried to cast doubt on the validity of Tabbush’s analysis. He suggested that the walnut tree was unrecognisable since it had grown in the seven years that had passed since the video was shot. According to Dzuro, this line of questioning only established that the counseel ‘didn’t have a clue about the science of trees’.
Tabbush’s response was courteous, but firm. Trees, he said, are actually more easily identified than people because ‘people are symmetrical on a central axis – whereas trees are not.’ He conceded that the tree had grown in the years since 1991, but insisted that that had no effect whatever on his analysis because ‘the branching had not changed at all’. He demonstrated to the court that there was a mathematical way of proving his point: a coefficient existed between the actual tree and the images on the video, which was clearly beyond mere chance or coincidence.
This established that the same tree not only appeared twice on the video, but had been filmed on opposite sides of the road to Dokmanović’s car. That proved he had not been travelling to the village of Negslavci, as his defence had claimed, but had actually been travelling back into Vukovar before the massacre took place. That meant that his video – and its time-codes – could only have been faked to provide Dokmanović with an alibi.
The effect of Tabbush’s testimony was immediate, dramatic and conclusive. Once the prosecution had proved Dokmanović had lied about his alibi, it was impossible to believe the other claims and statements that he had made under oath. Tabbush may not have convicted Dokmanović, but he did destroy his credibility as a witness and left the defence reeling.
Indeed, everyone in court that day seemed stunned by the scholarly elegance of Tabbush’s evidence, as well as by the sense of intellectual and moral integrity that he conveyed. It was as if two European traditions had faced each other across the Dutch courtroom. One was predicated on reasoned and measured analysis – the other on themes of blood and soil and murderous intent. But of course Tabbush would never have given his crucial evidence if it had not been for the painstaking and intuitive detective work of Vladimir Dzuro – and his relentless determination to bring some form of justice to the victims of the Vukovar massacre and their families.
On the night of June 29th, 1998 – a few days after Tabbush had testified and before a verdict had been given by the court – one of Dokmanović’s Dutch guards noticed that the light in his cell had gone out. When he went to check, he found that the former mayor of Vukovar had hanged himself. Perhaps the prospect of a long prison sentence had been too much for him to accept. Or perhaps, he had been compelled to think again about the friends and neighbours whom he had taken to be slaughtered – and, perhaps, facing that awful reality was finally too much for him to bear.
4/3/2025
