On the day an inquest jury returned an open verdict into the mysterious death of Cheung Chi-kin, his mother, Cheung So Tit-wa, visited his burial site and vowed justice would be done. The distraught mother told the Sunday Morning Post she was seeking legal advice as to whether the Correctional Services Department should be held liable for her son's death. 'During the period of his detention, I could still visit him,' she said. 'But right now, I can only hold my son's picture. Even when I cry, my son can't reply. I am not happy.' Mrs Cheung, a 50-something housewife who suffers from diabetes, said the last time she saw her son alive was in the Lai Chi Kok Reception Centre. She said he had smiled and comforted her while telling her not to worry as he was awaiting the drug report. The next time she saw her 26-year-old son in Tuen Mun Hospital on November 19, he was dead. It was then she noticed bruises and puncture wounds on his right shoulder. She also said she knew her son still had something to tell her as his eyes and mouth were open - signs interpreted in Chinese culture that the dead want to address a grievance. Since Chi-kin's death, Mrs Cheung faces the task of caring for her husband, who has been diagnosed with lung cancer, in their Tai Kok Tsui home. She said she had first become aware of her son's drug habit when he was 18. She had become suspicious because he was spending a lot of time in the family's bathroom. 'He said he took the drugs out of curiosity and the influence of his friends,' Mrs Cheung said, adding that her commitment to earning more money to buy a new home reduced the amount of time she had to spend with him. The situation came to a head when he slipped into petty crime to pay for his habit and was sentenced to undergo a drug addiction treatment programme. A tearful Mrs Cheung said she was forced to phone the authorities after she discovered her son, who had then been released from the treatment centre, was again using drugs. She said she could not remember how many times Chi-kin - the younger of her two sons - had been in and out of drug treatment centres. 'Though his income was very unstable, he gave me $200 on my or my husband's birthday and on festivals,' she said.