The killings came after two women were stabbed to death in the Plaza Hollywood shopping centre in Diamond Hill on Friday. The suspect, who was charged with two counts of murder, was receiving treatment at a government clinic and was just days away from his appointment when he was arrested.

The two incidents have put psychological services in the spotlight, with city leader John Lee Ka-chiu calling on residents to seek care if needed.

The NGO International Social Service said some 600 residents had visited a booth it set up in Sham Shui Po and eight required counselling.

Western Pacific Kindergarten, the multicultural school where the two older daughters were enrolled, said a crisis management team had been assembled and a parent meeting would be held soon.

“Under normal circumstances, parents are advised not to talk about the crisis incident with children if they are not affected by it to avoid causing them unnecessary traumas or emotional reactions,” the school said in a notice to parents.

Educational psychologists said teachers should pay close attention to the emotions of the victims’ closest friends in the coming weeks as should parents.

“It is not appropriate for teachers to break the news before the whole class, but instead they should talk to the students in small groups,” said Dr Amelia Lee Nam-yuk, an expert in child education.

Teachers should first check whether parents agreed to let the children learn about the deaths, she added.

Mall attack sparks calls for Hong Kong to overhaul mental health services

Developmental behavioural paediatrician Fanny Lam Wai-fan said both teachers and parents should be alert to any regressive behaviour in children, such as increased crying, noting they might only have a reaction after a long absence of their playmates.

“Teachers need to be particularly watchful to pick up signals,” she said.

Several parents said the school had not informed them of what was happening. Ada Tung, who has a child at Western Pacific, said no timely announcement was made because “the teachers probably do not know how to handle the situation”.

A father of another student, who only gave his surname as Ale, said he hoped the teachers would only say a classmate had gone missing without giving details as death was difficult to understand at such a young age.

The two incidents have also raised concerns that people with mental illnesses might be stigmatised by the public. The Red Cross said it had received about 100 calls for help since Friday, and more than a fifth were people who reported a mental illness, with some expressing concerns about how they would be labelled.

“They couldn’t sleep well or eat well,” clinical psychologist Eliza Cheung Yee-lai, who heads the psychological support service at the Hong Kong Red Cross, told a radio programme. “They were worried about whether they would be discriminated against or negatively labelled if they had mental illnesses.”

Cheung said some callers admitted they dared not tell others if their condition was worsening.

“They are worried that others will view them as a danger to the community and family members,” she said. “So they just keep to themselves.”

Hong Kong to review mental health services after man with ‘schizophrenia’ kills 2

She called for proper information to be disseminated, stressing the mall stabbing could lead to misconceptions about people in need, preventing them from seeking help.

“Most violent cases in the community are not caused by patients with mental illnesses, who on the other hand might be more easily victims of violence, according to some studies,” she said.

Psychiatrist Dr Chan Chung-mau, chairman of the Association for the Promotion of Mental Health, also expressed concern over stigmatisation of mental health patients.

“[Patients] are worried about being labelled and would consider mental illness something negative. They would pretend they did not have a disease,” Chan said. “We are worried that many patients would thus stop going to see doctors.”

Hou Wai-kai, an associate professor of psychology at the Education University of Hong Kong, suggested residents monitor how they consumed news of the deaths.

“One can read text, listen to others’ description or look at blurry photos,” Hou said. “You can then proceed to video if you want to know more, and in this case the impact would not be that strong.”

Number of Hong Kong students with mental health woes doubles in 4 years

City leader Lee said he was saddened by the deaths of the three girls and urged those in need to come forward if they needed help.

“I appeal to everyone to support each other with a kind heart, remind each other to seek help, and provide information to authorities if necessary,” he said. “The government hopes to intervene as soon as possible and provide assistance.”

Lee also pointed to talks and hotlines set up by the Social Welfare Department and relevant NGOs.

In the wake of last week’s mall stabbing, the government’s Advisory Committee on Mental Health on Friday will hold a meeting on improving services.

The session is expected to touch on psychiatric operations at public hospitals, the manpower of relevant professions, rehabilitation services and support for people recovering from mental illnesses in the community as well as for carers.

Topics such as addressing public misunderstanding towards people with mental health needs, and the handling of videos and information online involving violence will also be covered.

Additional reporting by Sammy Heung