THE HAGUE (Reuters) - The U.N. tribunal for former Yugoslavia said on Thursday an internal inquiry into the death in custody of prominent Serb war crimes suspect Slavko Dokmanovic found he hanged himself through no fault of jail officials. „All of the rules of the detention unit concerning security and safety were observed,“ tribunal spokesman Christian Chartier told a news conference. „No negligent behaviour was identified.“ Former Vukovar mayor Dokmanovic, 48, one of the biggest catches so far brought to trial before the U.N. court, was found hanging in his cell by prison guards just after midnight on Monday, June 29. He was awaiting the court‘s verdict. „He managed to hang himself by fastening on to the top door hinge of his cell‘s wardrobe the end of a…tie that he had firmly attached around his neck,“ Chartier said, presenting the findings of the inquiry led by tribunal judge Almiro Rodrigues. He said the inquiry found evidence that Dokmanovic had staged two earlier attempts that night to commit suicide, by cutting his veins and hanging himself, but that these escaped the attention of guards conducting half-hourly checks on his cell. Dokmanovic had been under half-hour surveillance during rest-time since June 23, the day before completion of his trial on charges relating to his alleged complicity in the massacre of more than 200 hospital patients in the eastern Croatian town of Vukovar in November 1991. He faced a maximum of life imprisonment if found guilty.