Hong Kong, China (CNN) -- Hundreds of Hong Kong residents gathered at a city plaza on Thursday to mourn the deaths of eight fellow citizens killed in the bus hostage drama in the Philippines, bowing their heads for three minutes of silence while some wept.
Chief Executive Donald Tsang led officials in a flag-raising and lowering to half-mast ceremony to remember the victims at Bauhinia Square, site where the city marked its 1997 handover to China.
"To be a Hong Kong citizen, we should do something to show we support all the families in this disaster," said Iris Yung, a housewife who attended with her daughter. "In Hong Kong people's minds, in the government's mind, those families become our families."
Flags in the Chinese territory have flown at half-mast at all government offices for three days beginning Tuesday. The Philippines also declared a national day of mourning on Wednesday, with flags lowered at public institutions across the country and at embassies and consulates overseas.
Seven other people were wounded Monday at the end of a 10-hour standoff that began when former police officer Rolando Mendoza commandeered their tourist bus at the edge of Rizal Park in Manila. It was the final day of vacation for the tour group which originated from Hong Kong.
Mendoza, a decorated officer who was apparently upset over the loss of his job, was killed by police but only after firing at the passengers.
Bodies of the dead victims, along with four of the seven wounded hostages, their family members and government officials returned home to Hong Kong from Manila aboard a charter flight Wednesday night.
The Hong Kong government has demanded a full investigation into the crisis and urged citizens not to express anger against Filipinos, an estimated 150,000 of whom work in Hong Kong, mostly as domestic workers.
"We believe it is imperative the investigation report at least [give] a detailed account of the whole incident, including the negotiation process, the police actions, and a detailed account of the causes of death and injury, whether they were all caused by shots fired by the gunman or otherwise," said Chief Secretary Henry Tang, who received the victims on their arrival.
Among the outstanding questions is whether victims were killed by Mendoza's or Philippine police bullets during the botched rescue operation and how the negotiation process was carried out.
Gen. Leocaldo Santiago, regional director of Manila Police, said police killed none of the hostages; a ballistics investigation has yet to be completed.
Hong Kong police is conducting an independent investigation.
At the Golden Bauhinia Square ceremony and at community centers in each of Hong Kong's 18 districts, people have paid their respects to the victims and their families, offering messages of sympathy.
By Thursday night when the "condolence points" had closed, about 37,900 people had signed those books throughout the territory, according to the Home Affairs Department on Friday.
The Filipino community in Hong Kong meanwhile organized vigils and Catholic masses through the week to remember the victims.
Antipathy toward the police handling of the Manila standoff remained high.
"Police kept firing [at the bus] and didn't care about the lives of Hong Kong people. When I watched the news, I felt very upset," said Jacko Kwan, 15.
A Hong Kong taxi driver, who would only be identified by his last name, Lau, said, "Most Hong Kong people think that Philippine SWAT are really amateurs ... Some say Philippine SWAT stands for 'Sorry We Aren't Trained'."
Jacqueline Chan brought her son to a community center near Happy Valley. "I wanted to show my son how to support others, let him know what is happening now and how to support the survivors," she said.
One couple who also marked the three minutes of silence at their home before traveling by subway to offer condolences at a community center in Quarry Bay said they had spent their honeymoon in 1974 in the Philippines. "We will never go to the Philippines again," said Kitty Mok, adding that she thought the tourists' deaths could have been prevented.
On Wednesday labor groups representing Filipino workers in Hong Kong held a press conference to express their condolences and demand justice for the bus hijacking. They also criticized Philippine President Benigno Aquino's statements after the tragedy as lacking "sensitivity and sensibility," questioning why he compared the hostage-taking to similar cases in Russia and Germany.
"We call on our own government to conduct an investigation to give justice to the victims," said Dolores Balladares, chairperson of United Filipinos in Hong Kong and member of the Filipino Migrant Workers Union.
Among the messages left in a condolence book Thursday by classmates Vyanne Chan and Judy Chan were blessings to the victims and their families and also hopes to not turn anger into further tragedy.
"I'd like to tell family members to live in a positive way and to be strong," Judy Chan said afterwards.