Catholic activist Jimmy Lai's trial on charges of violating a Chinese-imposed national security law is nearing the 100-day mark. He is the highest-profile Hong Kong resident to be tried under the law, and his case is considered a landmark case.

The trial of the 76-year-old pro-democracy advocate was suspended for a day June 3 after Lai's lawyers said he was not feeling well. They told the judge that Lai, who is being held in Hong Kong's Stanley Prison, had seen a doctor the previous night and had been prescribed painkillers. The trial resumed June 4, with one judge telling Lai he could notify the court if he felt unwell again.

Lai's son, Sebastien, has said his father suffers from diabetes and was diagnosed with high blood pressure while in prison in 2021.

For decades Lai, who founded the now-defunct pro-democracy Apple Daily, campaigned for freedom of the press and freedom of expression in Hong Kong, which was designated a Special Administrative Region of China in 1997, when British rule ended after more than 150 years. Hong Kong's Basic Law was supposed to allow the region "to exercise a high degree of autonomy and enjoy executive, legislative and independent judicial power, including that of final adjudication."

However, after a year of pro-democracy protests in 2019, China in 2020 Chin imposed the national security law, which has all but silenced dissent in Hong Kong, The Associated Press reported.

Under the law, Lai was arrested in August 2020 and has been imprisoned since December 2020. He has pleaded not guilty to two charges of conspiring to collude with foreign forces and one count of conspiring to publish seditious materials. If he is found guilty, he could face life in prison.

In January, Alice Jill Edwards, the U.N. special rapporteur on torture, said evidence in Lai's trial might have been obtained by torturing a witness in China.

In addition to the charges to which he has pleaded not guilty, in December 2021 Lai was convicted for his role in trying to commemorate the Tiananmen Square massacre in Beijing. The Chinese government said about 240 people were killed June 4, 1989, when Chinese tanks attacked protesters in the square; the Chinese Red Cross said 2,600 people were killed.

In August 2023, a Hong Kong Court of Appeal overturned the convictions of those accused of organizing an unlawful assembly, but it upheld their convictions for participating in an unlawful assembly.

In a June 4 commentary for ucanews.com, Benedict Rogers, a British human rights activist and CEO of Hong Kong Watch, said a secret cable from the British ambassador to China at the time put the Tiananmen Square death toll as high as 10,000. Rogers noted that until the imposition of the national security law, "Hong Kong was the only city under China's sovereignty that could still openly mark the anniversary."

Rogers -- named by prosecutors as one of the foreign agents with whom Lai colluded -- noted that Lai had served a "13-month sentence for lighting a candle and saying a prayer at a Tiananmen vigil."

"Let's remember also that the reason he founded the pro-democracy Next magazine in 1990 and the Apple Daily newspaper in 1995 was because he was so moved and shocked by the Beijing massacre," Rogers said.

Hong Kong Diocese's justice and peace commission often helped with commemorations of the Tiananmen massacre, and in 2009 Cardinal Joseph Zen called the victims martyrs who died to promote democracy and clean government in China. Lai has been Cardinal Zen's biggest financial backer.

In another ruling under the national security law, in late May a Hong Kong court convicted 14 pro-democracy activists, including several former lawmakers, of conspiracy to commit subversion. Those convicted were among hundreds of thousands of Hong Kong residents who voted in an unofficial primary election in July 2020.

The Associated Press reported election organizers had said they wanted to hold the Hong Kong government accountable by gaining a majority in the legislature, but the court ruled the unofficial election undermined the authority of the government.