A domestic helper was arrested after her employer - a government official - was hacked to death at her Causeway Bay home shortly before dawn yesterday. The Filipino maid, 35, was being held in the custodial ward of Kwai Chung Hospital for mental patients last night. No charges were laid. The victim was identified as Janice Kei Yin-lam, 47, a senior project manager for the Architectural Services Department. The killing occurred at about 4.40am. Residents heard an argument and cries for help in the 12th-floor flat in Illumination Terrace, Tai Hang Road, and alerted security guards. 'When my colleague went up to check, the maid ran out of the flat and tried to escape,' a security guard said. 'My colleague stopped her, and she ran back to the flat and closed the door. 'She was unarmed, but there was blood on her clothes. Bloodstained fingerprints were found on the flat's wooden door. He then called police.' Firefighters broke open a security gate that was locked from the inside. Ms Kei was found lying unconscious in the living room in a pool of blood. 'The victim suffered multiple and serious chop wounds, mainly in the abdomen,' a police source said. 'Her abdomen was chopped open. Blood was also splashed on the walls.' Paramedics declared Ms Kei dead at the scene, police said. An autopsy will be conducted today. The maid was found hiding in a bedroom, the police source said. She had suffered cut wounds to her fingers. 'Officers arrested her after brief resistance,' the source said. 'A bloodstained chopper was also found ... We suspect the maid has a mental problem.' At about 1pm, two elderly relatives of Ms Kei became dizzy at Wan Chai police station upon learning of her death. The couple was treated at Ruttonjee Hospital. Ms Kei spent about HK$8 million on the 910 sq ft flat last year, and recruited the helper in March. Ms Kei was described by the security guard as nice. A domestic helper who claimed to know the suspect said the employer was demanding. The Architectural Services Department said of Ms Kei: 'We deeply regret her death. We have contacted her family to provide assistance.' Vincent Ho Kui-yip, a council member of Hong Kong Institute of Surveyors' building surveying division, said Ms Kei was a senior member of the institute and had participated in training junior surveyors. There were 10 homicide cases in the first three months of this year, down from 14 in the same period last year. In March, a leading TV actress, Sonija Kwok Sin-nei, 34, had to be rescued by police in her luxury Kowloon City flat when her Indonesian maid bit her arm and refused to let go.