Eunice Lam

The mother of a 22-year-old woman who was stabbed to death in a random attack at a Diamond Hill mall on Friday thanked people who tried to save her, but urged people to stop sharing video footage of the attack.

A 39-year-old jobless man, Szeto, was arrested after allegedly stabbing two young women multiple times - Lau Kai-hei, 22, and her 26-year-old friend Fong Hiu-tung - with a foot-long knife inside Plaza Hollywood around 5.15 pm.

Szeto, diagnosed as suffering from mental illness, has been charged with two counts of murder and will appear at Kwun Tong magistrates' court today.

Police said the suspect did not know the victims.

A white candle was lit outside the Lau family home at King Lam Estate in Tseung Kwan O yesterday.

Lau's mother said she thought it was a sick joke when she was first informed that her daughter had died.

Lau and Fong, she said, were good friends, and the family was about to celebrate the birthday of Lau's younger sister, a junior secondary school student, on Saturday.

The mother said she was worried about her younger daughter as she was distraught after watching a video of the attack, and hoped people would stop sharing it online.

She thanked people who tried to save her daughter: "At least you guys tried your best to help our daughter."

Some people were seen giving the pair first aid at the scene, while a cook, Fai, at a Chinese restaurant was one of the few brave passersby who, armed with two stools, tried to stop the suspect.

Speaking on Saturday, Fai, 64, said he was having a meal when he heard the screams. "I only wanted to stop him from hurting people. But I didn't manage to help the two victims. I failed," he said.

Fong's mother said she heard about the tragedy during a dinner to celebrate the birthday of her daughter's 98-year-old grandfather, which Fong was to attend.

She hopes to have a chance to confront the suspect face to face. "Even if we are separated by a glass wall or an iron cage, I still want to ask him why."

Sources said Fong lived in Lung Mei Tsuen village in Tai Po - which is only 300 meters from another village house where model Abby Choi Tin-fung, 33, was dismembered in February.

Fong was said to have shared the flat with a couple on the second floor of a three-story house. She waitressed in Tsim Sha Tsui, while Lau was a hairstylist at a salon in the same area.

Szeto was seen buying a knife from a shop in the mall around 5 pm on the day, and attacked Lau and Fong in less than 15 minutes with the 12-inch-long knife.

Lau was pushed aside when she tried to rescue Fong. Szeto then stabbed Lau on the back as she laid wounded.

Sustaining multiple stab wounds, the pair was taken to United Christian Hospital. Fong was certified dead an hour later at 6.06 pm and Lau at 6.47 pm.

Police were seen patrolling the mall yesterday, while shops near the scene resumed operations.

People continued to lay flowers at the scene, and some were seen singing hymns and praying.

One of the bouquets was believed to have been sent by Lau's family. It bore a card that read "family members who will always love you."

A friend of Fong's, 17-year-old Ivan, said he only realized his friend had died after a WhatsApp message to her failed to go through. "I hope she will not have any of these incidents in her next life."

One of those who went to the scene, Wong, said more resources should be forthcoming for the mentally ill.