Since November 2015, we’ve been covering the story of a wave of arrests by authorities in the People’s Republic of China of publishers and booksellers associated with Causeway Bay Books, a publishing house and store in Hong Kong known for printing and selling thinly-sourced, gossipy books about members of China’s Communist Party leadership. The books are legal under Hong Kong law, but not mainland Chinese law (while Hong Kong is formally part of the PRC, it has its own discrete criminal justice system, under what Beijing calls its “One country, two systems” policy). Of the five Causeway Bay employees originally arrested, all but one—Swedish citizen Gui Minhai—have been released. One of them, Lam Wing-Kee, reported illegal treatment and harrowing conditions that drove him to attempt suicide during his detention.

Now, a staff report in the South China Morning Post alleges that China has jailed two more publishing professionals, Dai Xuelin and Zhang Xiaoxiong, both employees of Guangxi Normal University Press. The charges they faced, of running an “illegal business operation,” apparently arose from allegations that they had been contacting book distributors seeking access to materials legal in Hong Kong but not the mainland. Zhang was sentenced to three and a half years in prison, Dai to five.

Although both men live in Beijing, their case was handled by police and court officials in Ningbo, more than 800 miles away. Both Lam and another of the Causeway Bay detainees, Lee Po, reported being transported to Ningbo against their will during their detentions. And Gui, who grew up in Ningbo, was seen on Chinese state TV some time after his disappearance, delivering what had all the appearance of a forced confession. In it, he claimed he had returned to the Chinese mainland voluntarily to turn himself in for fleeing charges after he had accidentally killed a twenty-three-year-old student while driving drunk in Ningbo years earlier.

It’s not yet clear how the pieces here fit together, but a few facts are coming into focus. Firstly, it does not appear that authorities in the PRC are done prosecuting publishers and booksellers over books of political gossip produced in Hong Kong. And, in the absence of further information, there certainly appears to be something like a government task force taking shape in Ningbo, aimed at damming up the lively currents of Hong Kong’s free press. We’ll update this story as possible.