Yitu Technology has made an AI algorithm that can connect to millions of surveillance cameras and instantly recognise people.
The company – based in Shanghai, China – developed Dragonfly Eye to scan through millions of photographs that have been logged in the country's national database.
This means it has a collection of 1.8 billion photos on file, including visitors to the country and those taken at ports and airports.
It may also have access to the photos of every one of Hong Kong's identity card holders, although Yitu has refused to confirm this.
The cutting-edge technology is now being used track down criminals, with the early stages of use showing it has been a hugely successful.