Jimmy Lai Chee-ying. File photo: Xinhua

After the arrest of Jimmy Lai Chee-ying, founder of Apple Daily, for violating the national security law for Hong Kong, the Hong Kong Police Force searched the headquarters of Next Digital, parent company of Apple Daily, on Monday morning, as more executives from the notorious media group were arrested. 

Lai, the Hong Kong riot supporter, has been arrested for violating the national security law for Hong Kong for collusion with foreign powers, sources close to the Hong Kong Police Force confirmed with the Global Times on Monday morning. Police detained at least seven people during the operations.

Along with this arrest, two of Lai's sons and two senior executives from Next Digital - an executive chairman and a chairman in charge of the outlet's operation and finances - have also been arrested. One of Lai's aides, Mark Simon, is currently abroad and wanted by police. 

This was the first time the local media mogul, who is widely seen as a "modern traitor," was arrested for violating the law, which was enacted on June 30 and targets four types of criminal acts in the Hong Kong Special Administrative Region (HKSAR) - acts of secession, subversion of state power, terrorist activities and collusion with foreign forces to endanger national security. 

Some legal experts believe the case will involve a group charge of violating the national security law for Hong Kong, targeting the notorious local newspaper Apple Daily, which has played a role of instigating hatred, spreading rumors and smearing Hong Kong authorities and the mainland for years. It has also played an active role in inciting anti-government riots as it is backed and funded by foreign forces to bring about a "color revolution" in the city, experts said. 

The police said the operation is still ongoing and has not ruled out further arrests.

"It's likely that more personnel from the media outlet will be arrested," considering what the newspaper has done, Lawrence Tang Fei, a member of the Chinese Association of Hong Kong and Macao Studies, told the Global Times on Monday. 

Lai had been arrested multiple times over the past year on suspicion of participating in an unlawful assembly and intimidating journalists, defying police bans and clashing with police amid social turmoil across the city. But Lai had been also granted bail several times, and had travel bans imposed. 

"This time, for violating the national security law, it will be difficult for him to be granted bail again," Tian Feilong, a legal expert on Hong Kong affairs at Beihang University in Beijing, told the Global Times on Monday. 

The arrest also represents the most typical case of violation of the national security law for Hong Kong, and Lai is highly likely to face heavy penalties given that he has constantly challenged the law, Tian said. 

The law carries a maximum penalty of life imprisonment, with the chief perpetrator in particular likely to face severe punishment.

Local media also said that in addition to Lai, six other individuals, including his two sons, had also been arrested for collusion with foreign powers. Lai was also suspected of fraud, the sources said. 

While Western politicians, media outlets and activists paint Lai as a "hero" for democracy who has been "suppressed," many Chinese netizens cheered the arrest early Monday morning. 

"Finally, we see he is being arrested!" a netizen said in a Weibo post on Monday morning. "Never too late for justice," another netizen said.