Prison bosses must share the blame for the violent death of a Lai Chi Kok inmate, it was claimed yesterday. Wong Hing-kwok could have been saved if officers had gone to his aid as he was being brutally beaten by other prisoners, the High Court was told. 'One would expect CSD officers to be a little more diligent,' defence barrister Niall Stirling said. 'If they had been, perhaps this tragedy would never have unfolded.' The court had previously been told how a duty guard had ignored the victim's cries for help. Mrs Justice Verina Bokhary called on the Correctional Services Department (CSD) to investigate the incident as she jailed three inmates for manslaughter. Shao Ching-Yuen, 27, and Lin Man-king, 23, were each sentenced to four years in prison, while Cheung Chun-pong, 23, received a three-year term. 'It's very disturbing that a man should be killed while in CSD custody,' she said. 'I trust the CSD have looked into this and will further look into how to avoid any repetition.' Wong, 27, was said to have shouted for help when a group of inmates attacked him in his bunk on April 28 last year. His cries drew the duty guard, but the officer left again after one of the ring leaders said they were 'only playing'. Six other prisoners accused of being involved in the attack are on trial in the magistrates' court. They have been charged with assault occasioning actual bodily harm.