Police in Hong Kong have warned retailers to be aware of a Bitcoin blackmail operation linked to the ongoing protest activity.

Since early October, police have received four reports from different merchants that they received messages by fax or email since late September, coercing them to fund violent protests by Bitcoin. 

“The merchants were threatened to comply or their shops would be wrecked,” said a police spokesperson.

“Police accord high priority to such cases and are carrying out active investigations.”

The threats allegedly came from an unnamed “alliance” involved in protest activity, which another police spokesperson said claimed to protect Hong Kong’s democracy and freedom.

According to the South China Morning Post, an email written in Chinese to one of the businesses affected, which was published in Hong Kong local media, featured the word “HKwarriors” in English in the sender’s address.

The newspaper identified three businesses as victims of the emails: restaurant group Fulum, snack retailer Best Mart 360, and a health-products store Royal Medic.

The paper reported that an email to Fulum asked for the equivalent of HK$8000 and the message to Royal Medic about HK$40,000.

Police have urged any retailer or member of the public who has received such Bitcoin blackmail demands or any other intimidating messages – or who have any further information about the activity – to contact Hong Kong police by phone (5975 3133) or by email (appeal@police.gov.hk).