BEIJING/HONG KONG (Reuters) - Late last month, Shanghai resident Pei was one of many people who came out in support of historic protests against China's COVID-19 curbs, including filming several seconds of footage of a man being arrested on a street corner. 

Almost immediately, Pei said, five or six plainclothes police grabbed him. He was taken to a police station and held for 20 hours, at times with his arms and legs tied to a chair, he told Reuters.

"The policeman who shoved me into the car tried to intimidate me by saying I should be worried if other people find out what I did. Feeling defiant, I told him, I will let the world know what you police are doing," said Pei, 27. He asked to be identified only by part of his name for fear of repercussions.

Now, as many Chinese residents welcome a relaxation of lockdown measures that have crippled businesses and stoked unemployment, some protesters scooped up by China's security apparatus face an anxious wait about their fate.

While Pei and other protesters were released with a warning, some rights lawyers and academics note President Xi Jinping's hard line on dissent over the past decade, and say risks remain of further harassment and prosecution.

"'Squaring the accounts after the autumn harvests' is the Party's way of dealing with people who have betrayed it," said Lynette Ong, a University of Toronto professor, referring to the practice of delaying score settling until the time is ripe.

China's Ministry of Public Security did not respond to a request for comment on the laws they might use against protesters. The Shanghai police also did not immediately respond to a request for comment on Pei's description of how he was arrested or on what further actions they might take.

Last week, in a statement that did not refer to the protests, the Communist Party's top body in charge of law enforcement agencies said China would crack down on "the infiltration and sabotage activities of hostile forces" and would not tolerate any "illegal and criminal acts that disrupt social order".

Asked about the protests, China's foreign ministry has said rights and freedoms must be exercised lawfully.

FINES AND JAIL TIME?

Reuters was unable to establish how many protesters are still in police custody. Social media appeals for details on the whereabouts of a handful of missing protesters remain online.

The protests, widely seen as a tipping point to an easing in tight COVID restrictions, largely petered out in several cities after police mounted a heavy presence on streets.

The repercussions of protesting in China have grown in recent years under Xi's tenure, with the Ministry of Public Security introducing guidelines two years ago that have been used by local authorities to ban protesters from taking up jobs such as tour guides or insurance agents, and also make it harder for their family members to obtain government-related jobs.