International hackers alliance Anonymous’s Hong Kong division has said it will invade government websites and Chinese police websites in response to a Hong Kong bookseller’s suspected abduction by Chinese authorities.

Hong Kong publisher Lee Bo, a shareholder of the Causeway Bay Bookstore, went missing last week under suspicious circumstances. According to his wife, Lee disappeared after a trip to the bookstore’s warehouse. He later called from a Shenzhen number and said he was “assisting in an investigation,” his wife told police.

The Causeway Bay Bookstore is known for publishing racy tales about the private lives of Chinese leaders and internal power struggles in the Communist Party, many of which are hard to verify. Lee’s four other colleagues have gone missing in the mainland and in Thailand recently.

The serial disappearances have stoked fear in Hong Kong, with many accusing Beijing of abducting the victims in an attempt to crack down on the bookstore.

Anonymous HK published a video on its Facebook account on Saturday vowing to attack “any CCP website” over the incidents. “We cannot tolerate the China police who violated the section ‘One Country Two Systems’ and robbed those five Hong Kong citizens,” a figure behind a Guy Fawkes mask said.

The group posted a message late Sunday night saying hackers in Hong Kong and “overseas teams” were attempting to invade government information libraries and Chinese police websites. As of Monday morning, there have been no reports that any government website was hacked.

An abnormal message appears on the top of the Causeway Bay Bookstore’s website.

Anonymous HK also warned that the Causeway Bay Bookstore’s website has been compromised and warned readers not to purchase books via the site. Buyers’ information will be automatically sent to a third party, the group said on Facebook.

An abnormal message has appeared on the top of cwbbooks.com.