A woman was found dead in a disused toilet after a Correctional Services officer tied her up and covered her head with plastic bags, a jury heard yesterday. Manjit Singh, 25, is on trial for the murder of accounting clerk Tam Yim-hung, 35, who might have suffocated 26 hours into her ordeal last July, the Court of First Instance was told. Singh denies murder but has pleaded guilty to kidnapping Tam and stealing $17,900 from her bank account. He kidnapped the woman at knifepoint on the ground floor of her office building in Wyndham Street, Central, at about 2.30pm on July 6, the court heard. She was taken to the vacant seventh floor of the building and forced inside a toilet. Singh bound her arms and feet and covered her head first with two towels, then four plastic bags and another towel tied tightly around her neck, the court heard. The prosecutor said Singh then called Tam's home at various times from early on July 7 'with a mixture of lies, threats and demands for money'. He asked for $45,000 as repayment for debts, saying Tam was safe in a hotel in Macau, the court heard. The prosecution said one call was made to Tam's niece when Tam may have already been dead. Singh allegedly told police that he left the woman at 4pm on July 7 - an hour before the estimated time of death. The cause of death was asphyxia and strangulation. Police found Tam's body at 2.30am on July 8, after the niece reported her missing. Police traced the calls to Singh, who led them to her body. 'We don't know exactly what happened to Miss Tam during the 36 hours she was kept in that toilet. There is only one person in this courtroom that does know,' prosecutor Michael Arthur said. Singh admitted to police that he covered Tam's head with plastic bags and towels, but claimed he made holes in the bag. 'He also said that he had asked if she could breathe and she said that she could. The prosecution would say that this was almost certainly a lie,' Mr Arthur said. 'The towels themselves were enough to prevent the unfortunate Miss Tam from breathing.' A pathologist would testify that death would have been expected to follow within a few minutes of the bags and towels being tied around her head, the court heard. Mr Arthur claimed Singh must have learned about asphyxiation from his training as a correctional services officer. The trial continues before Madam Justice Clare-Marie Beeson.