This week RNZ exposed an unapproved police trial of controversial facial recognition software Clearview AI.
Described as a "search engine for faces" the technology is used by hundreds of police forces across the US and the world to help identify criminals and their victims.
Founded by Australian Hoan Ton-That, Clearview has assembled a database of 3 billion images scraped from social media platforms including Facebook, Instagram, and Twitter.
So why does Clearview AI cause such disquiet among privacy advocates? What do we know about the business, and how it operates? And do we really have anything to fear?