The phone, which from the outside appears no different from a normal device, issued warnings about using South Korean slang words to users, and auto-corrected “South Korea” to read “puppet state,” an investigation from the BBC found.

It would also covertly take a screenshot every five minutes, storing the images in a secret folder which the user couldn’t access, but which presumably were accessible to North Korean authorities. //

When the user tried to type in the word “oppa,” which means older brother in Korean, but has come to be used to refer to a boyfriend in South Korean slang, the phone would auto-correct the word to the more Communist-friendly alternative “comrade.”

A warning would then flash, informing the phone’s user that the term “oppa” could only be used for older siblings, the BBC investigation found.