A JURY yesterday returned a verdict of unlawful killing on a Vietnamese inmate stabbed in the heart. The dead man's cousin told the inquest that he witnessed the stabbing. The inquest into the death of Mr Nguyen Manh Cuong was called after a murder trial was aborted in October last year because a witness refused to give evidence. Mr Nguyen Van Bau was charged with the murder of Nguyen Manh Cuong, but was acquitted after the Crown offered no further evidence. The aborted trial was the subject of a commission of inquiry before Mr Justice Kempster earlier this year. Yesterday, Mr Nguyen Van Bau gave evidence to the Coroner's Court. Coroner Mr Richard Day repeatedly advised him that he was not obliged to answer questions. Mr Nguyen told the court he had been one of the heads of discipline at Whitehead Detention Centre at the time of Nguyen Manh Cuong's death on May 30, 1991. He said that peace committees patrolled detention camps to prevent people from stealing and dealt with other trivial matters. He said he could not remember whether or not he had been acquainted with the dead man. ''On the evening of May 30, 1991, did you meet Nguyen Manh Cuong?'' asked Coroner's Officer, Mr Michael Lunn. ''I don't want to answer,'' said Mr Nguyen. Summing up, Mr Day advised the jury that the court had heard no evidence to suggest that the man referred to as ''Ah Bau'' was Mr Nguyen Van Bau. He said: ''But even if there was [evidence], you could not name him because he has been charged with murder and has been acquitted.'' During the opening of the inquest on Wednesday, the cousin of the dead man, Mr Bui Van Xuan, said he saw ''Ah Bau'' stab Nguyen Manh Cuong shortly after the two had been involved in a dispute in the discipline room. Mr Day emphasised that the jury must not read anything into the fact that Mr Nguyen Van Bau told the court very little. The jury could not name anyone and accuse them of murder, he said. That person would not have had the protection of a criminal trial in which rules of evidence were more rigorous than in a coroner's court. Senior Police Inspector Mr Chan Chi-seung said the police were not making any further inquiries into the death.