People in the Hong Kong Special Administrative Region mourned an elderly man stoned to death two days ago, as violent protests continued to disrupt traffic and cause damage to properties in the city on Friday and even led to injuries to HK's justice chief in London.

The man, surnamed Luo, is the second citizen to be killed in a series of violent clashes amid social unrest since protests against the Extradition Bill erupted in the city in June. A number of other people have been injured, some seriously, including a man who was doused in flammable liquid and set on fire by radical protesters and remains hospitalized.

On Friday afternoon, a public memorial ceremony was held in Sheung Shui, northern Hong Kong, for people to send their condolences to the 70-year-old cleaner, who died in hospital on Thursday night after being stoned in the head by a brick cast from protesters during a Wednesday clash.

The "innocent man" was filming a clash between rioters and people who were clearing barricades they had set up, according to evidence acquired by the Hong Kong Police.

The case has been under investigation and classified as murder by the police.

Some CCTV cameras around the scene were damaged, which caused difficulties to the investigation, Senior Superintendent of Crime New Territories North Regional Headquarters Chan Tin-chu told the media at a press briefing on Friday.

He pledged that the police will pursue the case at all costs to bring the criminal to justice, and called on witnesses to provide more clues.

The Hong Kong Special Administrative Region government expressed outrage over the malicious acts of the rioters on Friday.

In a statement, the government's Food and Environmental Hygiene Department expressed profound sadness at the passing of the contractor cleaner, and said it is now providing necessary assistance to his family.

The Liaison Office of the Central People's Government in the HKSAR said the "inhumane and indiscriminate atrocity" is absolutely unacceptable. In a Friday statement, the office said violence must be stopped immediately to avoid more injuries.

Expressing deep condolences to the family of the deceased, it reiterated its firm support of the SAR government and the police to bring offenders to justice.

Justice chief attacked overseas

On Friday morning Beijing time (Thursday night in London), Hong Kong's Secretary for Justice Teresa Cheng Yeuk-wah was besieged and attacked by radical protesters in London on her way to an event. She fell down on the ground in chaos when dozens of radicals shouted and abused her in Cantonese while hustling.

In a statement, Cheng castigates the violent mob, and said she has immediately made a report to the London Police, and requested the police to take the case seriously and put the culprits to justice.

Chief Executive Carrie Lam Cheng Yuet-ngor on Friday expressed outrage over the attack on Cheng. Pointing out that the attack was barbaric and violated the principles of a civilized society, Lam said the act should be strongly condemned. She expressed hope that the local police will follow up on the case thoroughly to bring the offenders to justice.

In a daily press conference on Friday, China's Foreign Ministry also requested the United Kingdom to immediately follow up on the case thoroughly, and bring the offenders to justice, to safeguard the safety and dignity of all Chinese citizens in the UK.

Joining the condemnation are the Chinese Embassy in the UK, and the Foreign Ministry's Commissioner Office in the HKSAR.

"Bottom line" statement to world

On Thursday, President Xi Jinping stressed that the most pressing task for Hong Kong at present is to bring violence and chaos to an end and restore order, while he was attending the 11th BRICS summit in Brazil on Thursday.

"President Xi chose to make the statement at the BRICS Summit, as it could send a message to the world that China is determined to stop the violence," said Hong Kong business tycoon Allan Zeman, chairman of the Lan Kwai Fong Group.

He believed Xi's words could reassure Hong Kong society about the central government's support in the HKASR.

Tam Yiu-chung, a Hong Kong deputy to the National People's Congress Standing Committee – the country's top legislature – noted that Xi has twice made a stance on Hong Kong's situation in 10 days, but with stronger wording, while stressing China's opposition to any external force interfering in HKASR's affairs.

"It's a clear message to the international community on the central government's bottom line and firm stance," Tam said.

The SAR government has set up an interdepartmental coordination team chaired by Chief Secretary for Administration Matthew Cheung Kin-chung, to deal with the current social unrest, and introduce more decisive measures to end violence, Cheung said at a press conference on Friday.