Hong Kong police have arrested the founder of an online news site on suspicion of sedition, according to local media reports, the latest journalist to be detained as the city tightens its grip on the press.

Tang Ho-wing, founder of the digital platform Boom News, was arrested on Wednesday morning on suspicion of incitement by spreading disinformation, according to the Hong Kong newspaper Sing Tao. Authorities detained Mr. Tang early that morning, according to reports from Al Jazeera. The arrest was tied to a video involving a clash at Prince Edward metro station, the source of public grievance since police stormed subway trains there in 2019 during the city’s anti-government protests.

Press freedom advocates said the arrest was a new blow to a weakened media environment. Hong Kong has shut or driven out several independent outlets in recent years, and journalists there now work under the 2020 national security law imposed by Beijing and a homegrown addition passed in 2024. Sedition cases have been brought against protesters, writers and media figures.

It wasn’t clear on Thursday what charge, if any, Mr. Tang faced, or how long police could hold him without one. The Hong Kong police did not publicly name the suspect in the case.

Prince Edward station has remained a focus of public memory. Unsubstantiated claims that people died there in August 2019 circulated widely, and officials have denied them. The site’s long afterlife — and the public mistrust that kept the station in the news — has made anything connected to it politically sensitive.

Mr. Tang’s status after his arrest could not be determined. Boom News did not respond to a request for comment. Neither did the Hong Kong police force’s public relations office.