HONG KONG—Eight Hong Kong democracy activists, jailed in China last year after being captured at sea, arrived back in the city and were immediately detained on Monday in a case that has drawn international attention and concern over their treatment. They were among 12 activists facing charges in Hong Kong over pro-democracy protests, who were intercepted by mainland authorities in August 2020 on a boat allegedly en route to Taiwan. They were sent home to Hong Kong on Monday after serving a sentence in China for illegally crossing the border, only to be detained on arrival on the previous Hong Kong charges. Activist and barrister Chow Hang-tung, speaking on behalf of a concern group for the defendants, said she was unhappy with the handover arrangements for them. “(Authorities) never communicated with the family about the whole arrangement so the family members are forced to come here and wait all day …