A psychiatric patient accused of stabbing two women neighbours in Tin Shui Wai on Friday was described as emotionally stable during a check-up 10 days earlier.
The suspect, 30, was charged with two counts of wounding last night and will appear in court today. He was taken to the crime scene yesterday as part of the investigation and spent a second night detained at Castle Peak Hospital in Tuen Mun.
A psychiatrist, Dr Tsang Fan-kwong, said the behaviour of a mentally ill person could change dramatically even after he was assessed to be stable.
"He may become agitated by a sudden irritation, provocation, or a past dispute," Tsang said.
The women, aged 58 and 66, were attacked at about 3pm outside their public housing flat on Tin Shui Estate. The suspect was arrested at Tuen Mun Hospital the following day.
The victims were in stable condition last night.
Castle Peak Hospital said the man had been receiving psychiatric treatment since October last year. He turned up for regular follow-up consultations and was also under the watch of community psychiatric nurses.
The last medical consultation he attended was on November 13, just 10 days before the chopping attack. Doctors concluded at that time that his condition was emotionally stable.
Tsang cautioned that a single case did not imply mental assessments were problematic. Violence was very "diversified" and authorities had to look at the character, diagnosis and illness of the patient, he said.
The Secretary for Food and Health, Ko Wing-man, said the Hospital Authority would investigate why the man displayed such a change in behaviour in a relatively short period of time. In January a psychiatric patient aged 53 slashed a security guard to death with a chopper in Sheung Shui only three hours after visiting North District Hospital.