{At first he refused, but when they threatened to use a device to break into his Xiaomi 6 smartphone, he relented and entered the password. They then downloaded his chat records.
While searching his room, the officers backed down only after his parents complained, he said. The police officers implied that they had found him based on his phone number, which was linked to his identification.}
https://www.nytimes.com/2019/06/13/world/asia/hong-kong-telegram-protests.html